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Dietrich KA, Klüter S, Dinkel F, Echner G, Brons S, Orzada S, Debus J, Ladd ME, Platt T. An essentially radiation-transparent body coil integrated with a patient rotation system for MR-guided particle therapy. Med Phys 2024. [PMID: 38656549 DOI: 10.1002/mp.17065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 12/28/2023] [Accepted: 03/20/2024] [Indexed: 04/26/2024] Open
Abstract
BACKGROUND The pursuit of adaptive radiotherapy using MR imaging for better precision in patient positioning puts stringent demands on the hardware components of the MR scanner. Particularly in particle therapy, the dose distribution and thus the efficacy of the treatment is susceptible to beam attenuation from interfering materials in the irradiation path. This severely limits the usefulness of conventional imaging coils, which contain highly attenuating parts such as capacitors and preamplifiers in an unknown position, and requires development of a dedicated radiofrequency (RF) coil with close consideration of the materials and components used. PURPOSE In MR-guided radiation therapy in the human torso, imaging coils with a large FOV and homogeneous B1 field distribution are required for reliable tissue classification. In this work, an imaging coil for MR-guided particle therapy was developed with minimal ion attenuation while maintaining flexibility in treatment. METHODS A birdcage coil consisting of nearly radiation-transparent materials was designed and constructed for a closed-bore 1.5 T MR system. Additionally, the coil was mounted on a rotatable patient capsule for flexible positioning of the patient relative to the beam. The ion attenuation of the RF coil was investigated in theory and via measurements of the Bragg peak position. To characterize the imaging quality of the RF coil, transmit and receive field distributions were simulated and measured inside a homogeneous tissue-simulating phantom for various rotation angles of the patient capsule ranging from 0° to 345° in steps of 15°. Furthermore, simulations with a heterogeneous human voxel model were performed to better estimate the effect of real patient loading, and the RF coil was compared to the internal body coil in terms of SNR for a full rotation of the patient capsule. RESULTS The RF coil (total water equivalent thickness (WET) ≈ 420 µm, WET of conductor ≈ 210 µm) can be considered to be radiation-transparent, and a measured transmit power efficiency (B1 +/P $\sqrt {\mathrm{P}} $ ) between 0.17 µT/W $\sqrt {\mathrm{W}} $ and 0.26 µT/W $\sqrt {\mathrm{W}} $ could be achieved in a volume (Δz = 216 mm, complete x and y range) for the 24 investigated rotation angles of the patient capsule. Furthermore, homogeneous transmit and receive field distributions were measured and simulated in the transverse, coronal and sagittal planes in a homogeneous phantom and a human voxel model. In addition, the SNR of the radiation-transparent RF coil varied between 103 and 150, in the volume (Δz = 216 mm) of a homogeneous phantom and surpasses the SNR of the internal body coil for all rotation angles of the patient capsule. CONCLUSIONS A radiation-transparent RF coil was developed and built that enables flexible patient to beam positioning via full rotation capability of the RF coil and patient relative to the beam, with results providing promising potential for adaptive MR-guided particle therapy.
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Affiliation(s)
- Kilian A Dietrich
- Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Faculty of Physics, Heidelberg University, Heidelberg, Germany
- Clinical Cooperation Unit Radiation Oncology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Sebastian Klüter
- Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany
- National Center for Radiation Research in Oncology (NCRO), Heidelberg, Germany
- Heidelberg Institute of Radiation Oncology (HIRO), Heidelberg, Germany
| | - Fabian Dinkel
- Heidelberg Institute of Radiation Oncology (HIRO), Heidelberg, Germany
- Division of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Gernot Echner
- Heidelberg Institute of Radiation Oncology (HIRO), Heidelberg, Germany
- Division of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Stephan Brons
- Heidelberg Ion-Beam Therapy Center (HIT), Heidelberg University Hospital, Heidelberg, Germany
| | - Stephan Orzada
- Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Jürgen Debus
- Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany
- Faculty of Physics, Heidelberg University, Heidelberg, Germany
- Clinical Cooperation Unit Radiation Oncology, German Cancer Research Center (DKFZ), Heidelberg, Germany
- National Center for Radiation Research in Oncology (NCRO), Heidelberg, Germany
- Heidelberg Institute of Radiation Oncology (HIRO), Heidelberg, Germany
- Heidelberg Ion-Beam Therapy Center (HIT), Heidelberg University Hospital, Heidelberg, Germany
- German Cancer Consortium (DKTK), Heidelberg, Germany
- National Center for Tumor Diseases (NCT), Heidelberg, Germany
- Faculty of Medicine, Heidelberg University, Heidelberg, Germany
| | - Mark E Ladd
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Faculty of Physics, Heidelberg University, Heidelberg, Germany
- Faculty of Medicine, Heidelberg University, Heidelberg, Germany
| | - Tanja Platt
- Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Clinical Cooperation Unit Radiation Oncology, German Cancer Research Center (DKFZ), Heidelberg, Germany
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Brunheim S, Gratz M, Johst S, Bitz AK, Fiedler TM, Ladd ME, Quick HH, Orzada S. Erratum to: Fast and accurate multi-channel B1+ mapping based on the TIAMO technique for 7 Tesla UHF body MRI (Magn Reson Med 2018;79:2652-2664). Magn Reson Med 2024; 91:1735. [PMID: 38073053 DOI: 10.1002/mrm.29868] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2024]
Affiliation(s)
- S Brunheim
- MR Physics, German Center for Neurodegenerative Diseases (DZNE) within the Helmholtz Association, Bonn, Germany
| | - M Gratz
- Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany
- High Field and Hybrid MR Imaging, University Hospital Essen, Essen, Germany
| | - S Johst
- Gesellschaft für Anlagen- und Reaktorsicherheit (GRS) gGmbH, Cologne, Germany
| | - A K Bitz
- Electromagnetic Theory and Applied Mathematics, Faculty of Electrical Engineering and Information Technology, FH Aachen - University of Applied Sciences, Aachen, Germany
| | - T M Fiedler
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - M E Ladd
- Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - H H Quick
- Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany
- High Field and Hybrid MR Imaging, University Hospital Essen, Essen, Germany
| | - S Orzada
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
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Heiss R, Weber MA, Balbach EL, Hinsen M, Geissler F, Nagel AM, Ladd ME, Arkudas A, Horch RE, Gall C, Uder M, Roemer FW. Correction: Variation in cartilage T2 and T2* mapping of the wrist: a comparison between 3- and 7-T MRI. Eur Radiol Exp 2024; 8:48. [PMID: 38491230 PMCID: PMC10942944 DOI: 10.1186/s41747-024-00449-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/18/2024] Open
Affiliation(s)
- Rafael Heiss
- Department of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Maximiliansplatz 3, 91054, Erlangen, Germany.
| | - Marc-André Weber
- Institute of Diagnostic and Interventional Radiology, Pediatric Radiology and Neuroradiology, University Medical Center Rostock, Schillingallee 35, 18057, Rostock, Germany
| | - Eva L Balbach
- Department of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Maximiliansplatz 3, 91054, Erlangen, Germany
| | - Maximilian Hinsen
- Department of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Maximiliansplatz 3, 91054, Erlangen, Germany
| | - Frederik Geissler
- Department of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Maximiliansplatz 3, 91054, Erlangen, Germany
| | - Armin M Nagel
- Department of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Maximiliansplatz 3, 91054, Erlangen, Germany
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120, Heidelberg, Germany
| | - Mark E Ladd
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120, Heidelberg, Germany
- Faculty of Medicine and Faculty of Physics and Astronomy, Heidelberg University, Im Neuenheimer Feld 226, 69120, Heidelberg, Germany
| | - Andreas Arkudas
- Department of Plastic and Hand Surgery and Laboratory for Tissue Engineering and Regenerative Medicine, University Hospital Erlange, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Krankenhausstraße 12, 91054, Erlangen, Germany
| | - Raymund E Horch
- Department of Plastic and Hand Surgery and Laboratory for Tissue Engineering and Regenerative Medicine, University Hospital Erlange, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Krankenhausstraße 12, 91054, Erlangen, Germany
| | - Christine Gall
- Institute for Medical Informatics, Biometry and Epidemiology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Waldstraße 6, 91054, Erlangen, Germany
| | - Michael Uder
- Department of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Maximiliansplatz 3, 91054, Erlangen, Germany
| | - Frank W Roemer
- Department of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Maximiliansplatz 3, 91054, Erlangen, Germany
- Boston University School of Medicine, 72 E Concord St, Boston, MA, 02118, USA
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Franke VL, Breitling J, Boyd PS, Feignier A, Bangert R, Weckesser N, Schlemmer HP, Ladd ME, Bachert P, Paech D, Korzowski A. A versatile look-up algorithm for mapping pH values and magnesium ion content using 31 P MRSI. NMR Biomed 2024:e5113. [PMID: 38316107 DOI: 10.1002/nbm.5113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 11/21/2023] [Accepted: 01/11/2024] [Indexed: 02/07/2024]
Abstract
31 P MRSI allows for the non-invasive mapping of pH and magnesium ion content (Mg) in vivo, by translating the chemical shifts of inorganic phosphate and adenosine-5'-triphosphate (ATP) to pH and Mg via suitable calibration equations, such as the modified Henderson-Hasselbalch equation. However, the required constants in these calibration equations are typically only determined for physiological conditions, posing a particular challenge for their application to diseased tissue, where the biochemical conditions might change manyfold. In this article, we propose a multi-parametric look-up algorithm aiming at the condition-independent determination of pH and Mg by employing multiple quantifiable 31 P spectral properties simultaneously. To generate entries for an initial look-up table, measurements from 114 model solutions prepared with varying chemical properties were made at 9.4 T. The number of look-up table entries was increased by inter- and extrapolation using a multi-dimensional function developed based on the Hill equation. The assignment of biochemical parameters, that is, pH and Mg, is realized using probability distributions incorporating specific measurement uncertainties on the quantified spectral parameters, allowing for an estimation of most plausible output values. As proof of concept, we applied a version of the look-up algorithm employing only the chemical shifts of γ- and β-ATP for the determination of pH and Mg to in vivo 3D 31 P MRSI data acquired at 7 T from (i) the lower leg muscles of healthy volunteers and (ii) the brains of patients with glioblastoma. The resulting volumetric maps showed plausible values for pH and Mg, partly revealing differences from maps generated using the conventional calibration equations.
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Affiliation(s)
- Vanessa L Franke
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Johannes Breitling
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Philip S Boyd
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Antoine Feignier
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Renate Bangert
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Nina Weckesser
- Division of Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Heinz-Peter Schlemmer
- Division of Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Faculty of Medicine, Heidelberg University, Heidelberg, Germany
| | - Mark E Ladd
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Faculty of Medicine, Heidelberg University, Heidelberg, Germany
- Faculty of Physics and Astronomy, Heidelberg University, Heidelberg, Germany
| | - Peter Bachert
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Faculty of Physics and Astronomy, Heidelberg University, Heidelberg, Germany
| | - Daniel Paech
- Division of Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Division of Neuroradiology, University Hospital Bonn, Bonn, Germany
| | - Andreas Korzowski
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
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Ebersberger L, Kratzer FJ, Franke VL, Nagel AM, Niesporek SC, Korzowski A, Ladd ME, Schlemmer HP, Paech D, Platt T. First implementation of dynamic oxygen-17 ( 17O) magnetic resonance imaging at 7 Tesla during neuronal stimulation in the human brain. MAGMA 2024; 37:27-38. [PMID: 37737942 PMCID: PMC10876824 DOI: 10.1007/s10334-023-01119-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 08/27/2023] [Accepted: 08/31/2023] [Indexed: 09/23/2023]
Abstract
OBJECTIVE First implementation of dynamic oxygen-17 (17O) MRI at 7 Tesla (T) during neuronal stimulation in the human brain. METHODS Five healthy volunteers underwent a three-phase 17O gas (17O2) inhalation experiment. Combined right-side visual stimulus and right-hand finger tapping were used to achieve neuronal stimulation in the left cerebral hemisphere. Data analysis included the evaluation of the relative partial volume (PV)-corrected time evolution of absolute 17O water (H217O) concentration and of the relative signal evolution without PV correction. Statistical analysis was performed using a one-tailed paired t test. Blood oxygen level-dependent (BOLD) experiments were performed to validate the stimulation paradigm. RESULTS The BOLD maps showed significant activity in the stimulated left visual and sensorimotor cortex compared to the non-stimulated right side. PV correction of 17O MR data resulted in high signal fluctuations with a noise level of 10% due to small regions of interest (ROI), impeding further quantitative analysis. Statistical evaluation of the relative H217O signal with PV correction (p = 0.168) and without (p = 0.382) did not show significant difference between the stimulated left and non-stimulated right sensorimotor ROI. DISCUSSION The change of cerebral oxygen metabolism induced by sensorimotor and visual stimulation is not large enough to be reliably detected with the current setup and methodology of dynamic 17O MRI at 7 T.
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Affiliation(s)
- Louise Ebersberger
- German Cancer Research Center (DKFZ) Heidelberg, Division of Radiology, Heidelberg, Germany
- Faculty of Medicine, Ruprecht-Karls University Heidelberg, Heidelberg, Germany
- Department of Pediatrics, Bern University Hospital, Bern, Switzerland
| | - Fabian J Kratzer
- German Cancer Research Center (DKFZ) Heidelberg, Division of Medical Physics in Radiology, Heidelberg, Germany
| | - Vanessa L Franke
- German Cancer Research Center (DKFZ) Heidelberg, Division of Medical Physics in Radiology, Heidelberg, Germany
- Faculty of Physics and Astronomy, Ruprecht-Karls University Heidelberg, Heidelberg, Germany
| | - Armin M Nagel
- German Cancer Research Center (DKFZ) Heidelberg, Division of Medical Physics in Radiology, Heidelberg, Germany
- Institute of Radiology, Friedrich-Alexander University Hospital Erlangen-Nürnberg (FAU), University Hospital Erlangen, Erlangen, Germany
| | - Sebastian C Niesporek
- German Cancer Research Center (DKFZ) Heidelberg, Division of Medical Physics in Radiology, Heidelberg, Germany
| | - Andreas Korzowski
- German Cancer Research Center (DKFZ) Heidelberg, Division of Medical Physics in Radiology, Heidelberg, Germany
| | - Mark E Ladd
- Faculty of Medicine, Ruprecht-Karls University Heidelberg, Heidelberg, Germany
- German Cancer Research Center (DKFZ) Heidelberg, Division of Medical Physics in Radiology, Heidelberg, Germany
- Faculty of Physics and Astronomy, Ruprecht-Karls University Heidelberg, Heidelberg, Germany
| | - Heinz-Peter Schlemmer
- German Cancer Research Center (DKFZ) Heidelberg, Division of Radiology, Heidelberg, Germany
| | - Daniel Paech
- German Cancer Research Center (DKFZ) Heidelberg, Division of Radiology, Heidelberg, Germany
- Department of Neuroradiology, University Hospital Bonn, Bonn, Germany
| | - Tanja Platt
- German Cancer Research Center (DKFZ) Heidelberg, Division of Medical Physics in Radiology, Heidelberg, Germany.
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Zhang K, Triphan SMF, Wielpütz MO, Ziener CH, Ladd ME, Schlemmer HP, Kauczor HU, Kurz FT, Sedlaczek O. Simultaneous T 1, T 2 and T 2⁎ mapping of the liver with multi-shot MI-SAGE. Magn Reson Imaging 2024; 105:75-81. [PMID: 37939972 DOI: 10.1016/j.mri.2023.11.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Accepted: 11/04/2023] [Indexed: 11/10/2023]
Abstract
PURPOSE To apply multi-shot high-resolution multi inversion spin and gradient echo (MI-SAGE) acquisition for simultaneous liver T1, T2 and T2* mapping. METHODS Inversion prepared spin- and gradient-echo EPI was developed with ascending slice order across measurements for efficient acquisition with T1, T2, and T2⁎ weighting. Multi-shot EPI was also implemented to minimize distortion and blurring while enabling high in-plane resolution. A dictionary-matching approach was used to fit the images to quantitative parameter maps, which were compared to T1 measured by modified Look-Locker (MOLLI), T1 measured by variable flip angle (VFA), T2 measured by multiple echo time-based Half Fourier Single-shot Turbo spin-Echo (HASTE), T2 measured by radial turbo-spin-echo (rTSE) and T2⁎ measured by multiple gradient echo (MGRE) sequences. RESULTS The multi-shot variant of the sequence achieved higher in-plane resolution of 1.7 × 1.7 mm2 with good image quality in 28 s. Derived quantitative maps showed comparable values to conventional mapping methods. As measured in phantom and in vivo, MOLLI, MESE and MGRE give closest values to MISAGE. VFA, HASTE and rTSE show obvious overestimation. CONCLUSIONS The proposed multi-shot inversion prepared spin- and gradient-echo EPI sequence allows for high-resolution quantitative T1, T2 and T2 liver tissue characterization in a single breath-hold scan.
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Affiliation(s)
- Ke Zhang
- Department of Diagnostic & Interventional Radiology, Heidelberg University Hospital, Heidelberg, Germany; Translational Lung Research Center (TLRC), German Center for Lung Research (DZL), Heidelberg, Germany; Department of Diagnostic & Interventional Radiology with Nuclear Medicine, Thoraxklinik at Heidelberg University Hospital, Heidelberg, Germany
| | - Simon M F Triphan
- Department of Diagnostic & Interventional Radiology, Heidelberg University Hospital, Heidelberg, Germany; Translational Lung Research Center (TLRC), German Center for Lung Research (DZL), Heidelberg, Germany; Department of Diagnostic & Interventional Radiology with Nuclear Medicine, Thoraxklinik at Heidelberg University Hospital, Heidelberg, Germany
| | - Mark O Wielpütz
- Department of Diagnostic & Interventional Radiology, Heidelberg University Hospital, Heidelberg, Germany; Translational Lung Research Center (TLRC), German Center for Lung Research (DZL), Heidelberg, Germany; Department of Diagnostic & Interventional Radiology with Nuclear Medicine, Thoraxklinik at Heidelberg University Hospital, Heidelberg, Germany
| | - Christian H Ziener
- Divison of Radiology, German Cancer Research Center, Heidelberg, Germany
| | - Mark E Ladd
- Divison of Medical Physics in Radiology, German Cancer Research Center, Heidelberg, Germany; Faculty of Physics and Astronomy, Heidelberg University, Heidelberg, Germany; Faculty of Medicine, Heidelberg University, Heidelberg, Germany
| | | | - Hans-Ulrich Kauczor
- Department of Diagnostic & Interventional Radiology, Heidelberg University Hospital, Heidelberg, Germany; Translational Lung Research Center (TLRC), German Center for Lung Research (DZL), Heidelberg, Germany; Department of Diagnostic & Interventional Radiology with Nuclear Medicine, Thoraxklinik at Heidelberg University Hospital, Heidelberg, Germany
| | - Felix T Kurz
- Divison of Radiology, German Cancer Research Center, Heidelberg, Germany
| | - Oliver Sedlaczek
- Department of Diagnostic & Interventional Radiology, Heidelberg University Hospital, Heidelberg, Germany; Translational Lung Research Center (TLRC), German Center for Lung Research (DZL), Heidelberg, Germany; Department of Diagnostic & Interventional Radiology with Nuclear Medicine, Thoraxklinik at Heidelberg University Hospital, Heidelberg, Germany; Divison of Radiology, German Cancer Research Center, Heidelberg, Germany.
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Rauch J, Laun FB, Bachert P, Ladd ME, Kuder TA. Compensation of concomitant field effects in double diffusion encoding by means of added oscillating gradients. Magn Reson Imaging 2024; 105:133-141. [PMID: 37939973 DOI: 10.1016/j.mri.2023.11.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Accepted: 11/04/2023] [Indexed: 11/10/2023]
Abstract
Maxwell or concomitant fields imprint additional phases on the transverse magnetization. This concomitant phase may cause severe image artifacts like signal voids or distort the quantitative parameters due to the induced intravoxel dephasing. In particular, double diffusion encoding (DDE) schemes with two pairs of bipolar diffusion-weighting gradients separated by a refocusing radiofrequency (RF) pulse are prone to concomitant field-induced artifacts. In this work, a method for reducing concomitant field effects in these DDE sequences based on additional oscillating gradients is presented. These oscillating gradient pulses obtained by constrained optimization were added to the original gradient waveforms. The modified sequences reduced the accumulated concomitant phase without significant changes in the original sequence characteristics. The proposed method was applied to a DDE acquisition scheme consisting of 60 pairs of diffusion wave vectors. For phantom as well as for in vivo experiments, a considerable increase in the signal-to-noise ratio (SNR) was obtained. For phantom measurements with a diffusion weighting of b = 2000 s/mm2 for each of the gradient pairs, an SNR increase of up to 40% was observed for a transversal slice that had a distance of 5 cm from the isocenter. For equivalent slice parameters, in vivo measurements in the brain of a healthy volunteer exhibited an increase in SNR of up to 35% for b = 750 s/mm2 for each weighting. These findings are supported by corresponding simulations, which also predict a positive effect on the SNR. In summary, the presented method leads to an SNR gain without additional RF refocusing pulses.
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Affiliation(s)
- Julian Rauch
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany; MPI for Nuclear Physics, Max-Planck-Society, Saupfercheckweg 1, 69117 Heidelberg, Germany; Faculty of Physics and Astronomy, Heidelberg University, Im Neuenheimer Feld 226, 69120 Heidelberg, Germany
| | - Frederik B Laun
- Institute of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Maximiliansplatz 3, 91054 Erlangen, Germany
| | - Peter Bachert
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany; Faculty of Physics and Astronomy, Heidelberg University, Im Neuenheimer Feld 226, 69120 Heidelberg, Germany
| | - Mark E Ladd
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany; Faculty of Physics and Astronomy, Heidelberg University, Im Neuenheimer Feld 226, 69120 Heidelberg, Germany; Faculty of Medicine, Heidelberg University, Im Neuenheimer Feld 672, 69120 Heidelberg, Germany
| | - Tristan A Kuder
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany; Faculty of Physics and Astronomy, Heidelberg University, Im Neuenheimer Feld 226, 69120 Heidelberg, Germany.
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8
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Paech D, Weckesser N, Franke VL, Breitling J, Görke S, Deike-Hofmann K, Wick A, Scherer M, Unterberg A, Wick W, Bendszus M, Bachert P, Ladd ME, Schlemmer HP, Korzowski A. Whole-Brain Intracellular pH Mapping of Gliomas Using High-Resolution 31P MR Spectroscopic Imaging at 7.0 T. Radiol Imaging Cancer 2024; 6:e220127. [PMID: 38133553 PMCID: PMC10825708 DOI: 10.1148/rycan.220127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2022] [Revised: 10/24/2023] [Accepted: 11/02/2023] [Indexed: 12/23/2023]
Abstract
Malignant tumors commonly exhibit a reversed pH gradient compared with normal tissue, with a more acidic extracellular pH and an alkaline intracellular pH (pHi). In this prospective study, pHi values in gliomas were quantified using high-resolution phosphorous 31 (31P) spectroscopic MRI at 7.0 T and were used to correlate pHi alterations with histopathologic findings. A total of 12 participants (mean age, 58 years ± 18 [SD]; seven male, five female) with histopathologically proven, newly diagnosed glioma were included between September 2018 and November 2019. The 31P spectroscopic MRI scans were acquired using a double-resonant 31P/1H phased-array head coil together with a three-dimensional (3D) 31P chemical shift imaging sequence (5.7-mL voxel volume) performed with a 7.0-T whole-body system. The 3D volumetric segmentations were performed for the whole-tumor volumes (WTVs); tumor subcompartments of necrosis, gadolinium enhancement, and nonenhancing T2 (NCE T2) hyperintensity; and normal-appearing white matter (NAWM), and pHi values were compared. Spearman correlation was used to assess association between pHi and the proliferation index Ki-67. For all study participants, mean pHi values were higher in the WTV (7.057 ± 0.024) compared with NAWM (7.006 ± 0.012; P < .001). In eight participants with high-grade gliomas, pHi was increased in all tumor subcompartments (necrosis, 7.075 ± 0.033; gadolinium enhancement, 7.075 ± 0.024; NCE T2 hyperintensity, 7.043 ± 0.015) compared with NAWM (7.004 ± 0.014; all P < .01). The pHi values of WTV positively correlated with Ki-67 (R2 = 0.74, r = 0.78, P = .001). In conclusion, 31P spectroscopic MRI at 7.0 T enabled high-resolution quantification of pHi in gliomas, with pHi alteration associated with the Ki-67 proliferation index, and may aid in diagnosis and treatment monitoring. Keywords: 31P MRSI, pH, Glioma, Glioblastoma, Ultra-High-Field MRI, Imaging Biomarker, 7 Tesla Supplemental material is available for this article. © RSNA, 2023.
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Affiliation(s)
| | | | - Vanessa L. Franke
- From the Divisions of Radiology (D.P., N.W., K.D.H., H.P.S.) and
Medical Physics in Radiology (V.L.F., J.B., S.G., P.B., M.E.L., A.K.), German
Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg,
Germany; Faculties of Medicine (N.W., M.E.L.) and Physics and Astronomy (V.L.F.,
P.B., M.E.L.), University of Heidelberg, Heidelberg, Germany; and Departments of
Neurology (A.W., W.W.), Neurosurgery (M.S., A.U.), and Neuroradiology (M.B.),
Heidelberg University Hospital, Heidelberg, Germany
| | - Johannes Breitling
- From the Divisions of Radiology (D.P., N.W., K.D.H., H.P.S.) and
Medical Physics in Radiology (V.L.F., J.B., S.G., P.B., M.E.L., A.K.), German
Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg,
Germany; Faculties of Medicine (N.W., M.E.L.) and Physics and Astronomy (V.L.F.,
P.B., M.E.L.), University of Heidelberg, Heidelberg, Germany; and Departments of
Neurology (A.W., W.W.), Neurosurgery (M.S., A.U.), and Neuroradiology (M.B.),
Heidelberg University Hospital, Heidelberg, Germany
| | - Steffen Görke
- From the Divisions of Radiology (D.P., N.W., K.D.H., H.P.S.) and
Medical Physics in Radiology (V.L.F., J.B., S.G., P.B., M.E.L., A.K.), German
Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg,
Germany; Faculties of Medicine (N.W., M.E.L.) and Physics and Astronomy (V.L.F.,
P.B., M.E.L.), University of Heidelberg, Heidelberg, Germany; and Departments of
Neurology (A.W., W.W.), Neurosurgery (M.S., A.U.), and Neuroradiology (M.B.),
Heidelberg University Hospital, Heidelberg, Germany
| | - Katerina Deike-Hofmann
- From the Divisions of Radiology (D.P., N.W., K.D.H., H.P.S.) and
Medical Physics in Radiology (V.L.F., J.B., S.G., P.B., M.E.L., A.K.), German
Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg,
Germany; Faculties of Medicine (N.W., M.E.L.) and Physics and Astronomy (V.L.F.,
P.B., M.E.L.), University of Heidelberg, Heidelberg, Germany; and Departments of
Neurology (A.W., W.W.), Neurosurgery (M.S., A.U.), and Neuroradiology (M.B.),
Heidelberg University Hospital, Heidelberg, Germany
| | - Antje Wick
- From the Divisions of Radiology (D.P., N.W., K.D.H., H.P.S.) and
Medical Physics in Radiology (V.L.F., J.B., S.G., P.B., M.E.L., A.K.), German
Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg,
Germany; Faculties of Medicine (N.W., M.E.L.) and Physics and Astronomy (V.L.F.,
P.B., M.E.L.), University of Heidelberg, Heidelberg, Germany; and Departments of
Neurology (A.W., W.W.), Neurosurgery (M.S., A.U.), and Neuroradiology (M.B.),
Heidelberg University Hospital, Heidelberg, Germany
| | - Moritz Scherer
- From the Divisions of Radiology (D.P., N.W., K.D.H., H.P.S.) and
Medical Physics in Radiology (V.L.F., J.B., S.G., P.B., M.E.L., A.K.), German
Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg,
Germany; Faculties of Medicine (N.W., M.E.L.) and Physics and Astronomy (V.L.F.,
P.B., M.E.L.), University of Heidelberg, Heidelberg, Germany; and Departments of
Neurology (A.W., W.W.), Neurosurgery (M.S., A.U.), and Neuroradiology (M.B.),
Heidelberg University Hospital, Heidelberg, Germany
| | - Andreas Unterberg
- From the Divisions of Radiology (D.P., N.W., K.D.H., H.P.S.) and
Medical Physics in Radiology (V.L.F., J.B., S.G., P.B., M.E.L., A.K.), German
Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg,
Germany; Faculties of Medicine (N.W., M.E.L.) and Physics and Astronomy (V.L.F.,
P.B., M.E.L.), University of Heidelberg, Heidelberg, Germany; and Departments of
Neurology (A.W., W.W.), Neurosurgery (M.S., A.U.), and Neuroradiology (M.B.),
Heidelberg University Hospital, Heidelberg, Germany
| | - Wolfgang Wick
- From the Divisions of Radiology (D.P., N.W., K.D.H., H.P.S.) and
Medical Physics in Radiology (V.L.F., J.B., S.G., P.B., M.E.L., A.K.), German
Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg,
Germany; Faculties of Medicine (N.W., M.E.L.) and Physics and Astronomy (V.L.F.,
P.B., M.E.L.), University of Heidelberg, Heidelberg, Germany; and Departments of
Neurology (A.W., W.W.), Neurosurgery (M.S., A.U.), and Neuroradiology (M.B.),
Heidelberg University Hospital, Heidelberg, Germany
| | - Martin Bendszus
- From the Divisions of Radiology (D.P., N.W., K.D.H., H.P.S.) and
Medical Physics in Radiology (V.L.F., J.B., S.G., P.B., M.E.L., A.K.), German
Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg,
Germany; Faculties of Medicine (N.W., M.E.L.) and Physics and Astronomy (V.L.F.,
P.B., M.E.L.), University of Heidelberg, Heidelberg, Germany; and Departments of
Neurology (A.W., W.W.), Neurosurgery (M.S., A.U.), and Neuroradiology (M.B.),
Heidelberg University Hospital, Heidelberg, Germany
| | - Peter Bachert
- From the Divisions of Radiology (D.P., N.W., K.D.H., H.P.S.) and
Medical Physics in Radiology (V.L.F., J.B., S.G., P.B., M.E.L., A.K.), German
Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg,
Germany; Faculties of Medicine (N.W., M.E.L.) and Physics and Astronomy (V.L.F.,
P.B., M.E.L.), University of Heidelberg, Heidelberg, Germany; and Departments of
Neurology (A.W., W.W.), Neurosurgery (M.S., A.U.), and Neuroradiology (M.B.),
Heidelberg University Hospital, Heidelberg, Germany
| | - Mark E. Ladd
- From the Divisions of Radiology (D.P., N.W., K.D.H., H.P.S.) and
Medical Physics in Radiology (V.L.F., J.B., S.G., P.B., M.E.L., A.K.), German
Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg,
Germany; Faculties of Medicine (N.W., M.E.L.) and Physics and Astronomy (V.L.F.,
P.B., M.E.L.), University of Heidelberg, Heidelberg, Germany; and Departments of
Neurology (A.W., W.W.), Neurosurgery (M.S., A.U.), and Neuroradiology (M.B.),
Heidelberg University Hospital, Heidelberg, Germany
| | - Heinz-Peter Schlemmer
- From the Divisions of Radiology (D.P., N.W., K.D.H., H.P.S.) and
Medical Physics in Radiology (V.L.F., J.B., S.G., P.B., M.E.L., A.K.), German
Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg,
Germany; Faculties of Medicine (N.W., M.E.L.) and Physics and Astronomy (V.L.F.,
P.B., M.E.L.), University of Heidelberg, Heidelberg, Germany; and Departments of
Neurology (A.W., W.W.), Neurosurgery (M.S., A.U.), and Neuroradiology (M.B.),
Heidelberg University Hospital, Heidelberg, Germany
| | - Andreas Korzowski
- From the Divisions of Radiology (D.P., N.W., K.D.H., H.P.S.) and
Medical Physics in Radiology (V.L.F., J.B., S.G., P.B., M.E.L., A.K.), German
Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg,
Germany; Faculties of Medicine (N.W., M.E.L.) and Physics and Astronomy (V.L.F.,
P.B., M.E.L.), University of Heidelberg, Heidelberg, Germany; and Departments of
Neurology (A.W., W.W.), Neurosurgery (M.S., A.U.), and Neuroradiology (M.B.),
Heidelberg University Hospital, Heidelberg, Germany
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9
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Heiss R, Weber MA, Balbach EL, Hinsen M, Geissler F, Nagel AM, Ladd ME, Arkudas A, Horch RE, Gall C, Uder M, Roemer FW. Variation in cartilage T2 and T2* mapping of the wrist: a comparison between 3- and 7-T MRI. Eur Radiol Exp 2023; 7:80. [PMID: 38093075 PMCID: PMC10719234 DOI: 10.1186/s41747-023-00394-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Accepted: 09/30/2023] [Indexed: 12/17/2023] Open
Abstract
BACKGROUND To analyze regional variations in T2 and T2* relaxation times in wrist joint cartilage and the triangular fibrocartilage complex (TFCC) at 3 and 7 T and to compare values between field strengths. METHODS Twenty-five healthy controls and 25 patients with chronic wrist pain were examined at 3 and 7 T on the same day using T2- and T2*-weighted sequences. Six different regions of interest (ROIs) were evaluated for cartilage and 3 ROIs were evaluated at the TFCC based on manual segmentation. Paired t-tests were used to compare T2 and T2* values between field strengths and between different ROIs. Spearman's rank correlation was calculated to assess correlations between T2 and T2* time values at 3 and 7 T. RESULTS T2 and T2* time values of the cartilage differed significantly between 3 and 7 T for all ROIs (p ≤ 0.045), with one exception: at the distal lunate, no significant differences in T2 values were observed between field strengths. T2* values differed significantly between 3 and 7 T for all ROIs of the TFCC (p ≤ 0.001). Spearman's rank correlation between 3 and 7 T ranged from 0.03 to 0.62 for T2 values and from 0.01 to 0.48 for T2* values. T2 and T2* values for cartilage varied across anatomic locations in healthy controls at both 3 and 7 T. CONCLUSION Quantitative results of T2 and T2* mapping at the wrist differ between field strengths, with poor correlation between 3 and 7 T. Local variations in cartilage T2 and T2* values are observed in healthy individuals. RELEVANCE STATEMENT T2 and T2* mapping are feasible for compositional imaging of the TFCC and the cartilage at the wrist at both 3 and 7 T, but the clinical interpretation remains challenging due to differences between field strengths and variations between anatomic locations. KEY POINTS •Field strength and anatomic locations influence T2 and T2* values at the wrist. •T2 and T2* values have a poor correlation between 3 and 7 T. •Local reference values are needed for each anatomic location for reliable interpretation.
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Affiliation(s)
- Rafael Heiss
- Department of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Maximiliansplatz 3, 91054, Erlangen, Germany.
| | - Marc-André Weber
- Institute of Diagnostic and Interventional Radiology, Pediatric Radiology and Neuroradiology, University Medical Center Rostock, Schillingallee 35, 18057, Rostock, Germany
| | - Eva L Balbach
- Department of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Maximiliansplatz 3, 91054, Erlangen, Germany
| | - Maximilian Hinsen
- Department of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Maximiliansplatz 3, 91054, Erlangen, Germany
| | - Frederik Geissler
- Department of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Maximiliansplatz 3, 91054, Erlangen, Germany
| | - Armin M Nagel
- Department of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Maximiliansplatz 3, 91054, Erlangen, Germany
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120, Heidelberg, Germany
| | - Mark E Ladd
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120, Heidelberg, Germany
- Faculty of Medicine and Faculty of Physics and Astronomy, Heidelberg University, Im Neuenheimer Feld 226, 69120, Heidelberg, Germany
| | - Andreas Arkudas
- Department of Plastic and Hand Surgery and Laboratory for Tissue Engineering and Regenerative Medicine, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Krankenhausstraße 12, 91054, Erlangen, Germany
| | - Raymund E Horch
- Department of Plastic and Hand Surgery and Laboratory for Tissue Engineering and Regenerative Medicine, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Krankenhausstraße 12, 91054, Erlangen, Germany
| | - Christine Gall
- Institute for Medical Informatics, Biometry and Epidemiology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Waldstraße 6, 91054, Erlangen, Germany
| | - Michael Uder
- Department of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Maximiliansplatz 3, 91054, Erlangen, Germany
| | - Frank W Roemer
- Department of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Maximiliansplatz 3, 91054, Erlangen, Germany
- Boston University School of Medicine, 72 E Concord St, Boston, MA, 02118, USA
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10
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Ladd ME. The Medical Device Regulation and its impact on device development and research in Germany. Z Med Phys 2023; 33:459-461. [PMID: 37863758 PMCID: PMC10751713 DOI: 10.1016/j.zemedi.2023.09.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2023]
Affiliation(s)
- Mark E Ladd
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany; Faculty of Physics and Astronomy & Faculty of Medicine, Heidelberg University, Heidelberg, Germany; Erwin L. Hahn Institute for MRI, University Duisburg-Essen, Essen, Germany
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11
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von Knebel Doeberitz N, Kroh F, König L, Boyd PS, Graß S, Bauspieß C, Scherer M, Unterberg A, Bendszus M, Wick W, Bachert P, Debus J, Ladd ME, Schlemmer HP, Goerke S, Korzowski A, Paech D. Post-Surgical Depositions of Blood Products Are No Major Confounder for the Diagnostic and Prognostic Performance of CEST MRI in Patients with Glioma. Biomedicines 2023; 11:2348. [PMID: 37760790 PMCID: PMC10525358 DOI: 10.3390/biomedicines11092348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 08/11/2023] [Accepted: 08/16/2023] [Indexed: 09/29/2023] Open
Abstract
Amide proton transfer (APT) and semi-solid magnetization transfer (ssMT) imaging can predict clinical outcomes in patients with glioma. However, the treatment of brain tumors is accompanied by the deposition of blood products within the tumor area in most cases. For this reason, the objective was to assess whether the diagnostic interpretation of the APT and ssMT is affected by methemoglobin (mHb) and hemosiderin (Hs) depositions at the first follow-up MRI 4 to 6 weeks after the completion of radiotherapy. A total of 34 participants underwent APT and ssMT imaging by applying reconstruction methods described by Zhou et al. (APTwasym), Goerke et al. (MTRRexAPT and MTRRexMT) and Mehrabian et al. (MTconst). Contrast-enhancing tumor (CE), whole tumor (WT), mHb and Hs were segmented on contrast-enhanced T1wCE, T2w-FLAIR, T1w and T2*w images. ROC-analysis, Kaplan-Meier analysis and the log rank test were used to test for the association of mean contrast values with therapy response and overall survival (OS) before (WT and CE) and after correcting tumor volumes for mHb and Hs (CEC and WTC). CEC showed higher associations of the MTRRexMT with therapy response (CE: AUC = 0.677, p = 0.081; CEC: AUC = 0.705, p = 0.044) and of the APTwasym with OS (CE: HR = 2.634, p = 0.040; CEC: HR = 2.240, p = 0.095). In contrast, WTC showed a lower association of the APTwasym with survival (WT: HR = 2.304, p = 0.0849; WTC: HR = 2.990, p = 0.020). Overall, a sophisticated correction for blood products did not substantially influence the clinical performance of APT and ssMT imaging in patients with glioma early after radiotherapy.
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Affiliation(s)
| | - Florian Kroh
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
- Department of Physics and Astronomy, University of Heidelberg, 69120 Heidelberg, Germany
| | - Laila König
- Department of Radiation Oncology, Heidelberg University Hospital, 69120 Heidelberg, Germany
| | - Philip S. Boyd
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
| | - Svenja Graß
- Division of Radiology, German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
| | - Cora Bauspieß
- Division of Radiology, German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
| | - Moritz Scherer
- Department of Neurosurgery, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Andreas Unterberg
- Department of Neurosurgery, University Hospital Heidelberg, 69120 Heidelberg, Germany
- Faculty of Medicine, University of Heidelberg, 69120 Heidelberg, Germany
| | - Martin Bendszus
- Faculty of Medicine, University of Heidelberg, 69120 Heidelberg, Germany
- Department of Neuroradiology, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Wolfgang Wick
- Faculty of Medicine, University of Heidelberg, 69120 Heidelberg, Germany
- Department of Neurology, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Peter Bachert
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
- Department of Physics and Astronomy, University of Heidelberg, 69120 Heidelberg, Germany
| | - Jürgen Debus
- Department of Radiation Oncology, Heidelberg University Hospital, 69120 Heidelberg, Germany
- Faculty of Medicine, University of Heidelberg, 69120 Heidelberg, Germany
- Clinical Cooperation Unit Radiation Oncology, German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
| | - Mark E. Ladd
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
- Department of Physics and Astronomy, University of Heidelberg, 69120 Heidelberg, Germany
- Faculty of Medicine, University of Heidelberg, 69120 Heidelberg, Germany
| | - Heinz-Peter Schlemmer
- Division of Radiology, German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
- Faculty of Medicine, University of Heidelberg, 69120 Heidelberg, Germany
| | - Steffen Goerke
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
| | - Andreas Korzowski
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
| | - Daniel Paech
- Division of Radiology, German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
- Department of Neuroradiology, University Hospital Bonn, 53127 Bonn, Germany
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12
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Ebersberger L, Kratzer FJ, Potreck A, Niesporek SC, Keymling M, Nagel AM, Bendszus M, Wick W, Ladd ME, Schlemmer HP, Hoffmann A, Platt T, Paech D. First application of dynamic oxygen-17 magnetic resonance imaging at 7 Tesla in a patient with early subacute stroke. Front Neurosci 2023; 17:1186558. [PMID: 37404469 PMCID: PMC10317041 DOI: 10.3389/fnins.2023.1186558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Accepted: 05/26/2023] [Indexed: 07/06/2023] Open
Abstract
Dynamic oxygen-17 (17O) magnetic resonance imaging (MRI) is an imaging method that enables a direct and non-invasive assessment of cerebral oxygen metabolism and thus potentially the distinction between viable and non-viable tissue employing a three-phase inhalation experiment. The purpose of this investigation was the first application of dynamic 17O MRI at 7 Tesla (T) in a patient with stroke. In this proof-of-concept experiment, dynamic 17O MRI was applied during 17O inhalation in a patient with early subacute stroke. The analysis of the relative 17O water (H217O) signal for the affected stroke region compared to the healthy contralateral side revealed no significant difference. However, the technical feasibility of 17O MRI has been demonstrated paving the way for future investigations in neurovascular diseases.
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Affiliation(s)
- Louise Ebersberger
- Division of Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Faculty of Medicine, University of Heidelberg, Heidelberg, Germany
| | - Fabian J. Kratzer
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Arne Potreck
- Department of Neuroradiology, Heidelberg University Hospital, Heidelberg, Germany
| | - Sebastian C. Niesporek
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Myriam Keymling
- Division of Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Armin M. Nagel
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Institute of Radiology, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Erlangen University Hospital, Erlangen, Germany
| | - Martin Bendszus
- Department of Neuroradiology, Heidelberg University Hospital, Heidelberg, Germany
| | - Wolfgang Wick
- Department of Neurology, Heidelberg University Hospital, Heidelberg, Germany
| | - Mark E. Ladd
- Faculty of Medicine, University of Heidelberg, Heidelberg, Germany
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Faculty of Physics and Astronomy, University of Heidelberg, Heidelberg, Germany
| | | | - Angelika Hoffmann
- Department of Neuroradiology, Heidelberg University Hospital, Heidelberg, Germany
- Department of Neuroradiology, Bern University Hospital, Bern, Switzerland
| | - Tanja Platt
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Daniel Paech
- Division of Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Department of Neuroradiology, Bonn University Hospital, Bonn, Germany
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13
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Kroh F, von Knebel Doeberitz N, Breitling J, Maksimovic S, König L, Adeberg S, Scherer M, Unterberg A, Bendszus M, Wick W, Bachert P, Debus J, Ladd ME, Schlemmer HP, Korzowski A, Goerke S, Paech D. Semi-solid MT and APTw CEST-MRI predict clinical outcome of patients with glioma early after radiotherapy. Magn Reson Med 2023. [PMID: 37317562 DOI: 10.1002/mrm.29746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 04/20/2023] [Accepted: 05/18/2023] [Indexed: 06/16/2023]
Abstract
PURPOSE The purpose of this study was to compare the potential of asymmetry-based (APTwasym ), Lorentzian-fit-based (PeakAreaAPT and MTconst ), and relaxation-compensated (MTRRex APT and MTRRex MT) CEST contrasts of the amide proton transfer (APT) and semi-solid magnetization transfer (ssMT) for early response assessment and prediction of progression-free survival (PFS) in patients with glioma. METHODS Seventy-two study participants underwent CEST-MRI at 3T from July 2018 to December 2021 in a prospective clinical trial four to 6 wk after the completion of radiotherapy for diffuse glioma. Tumor segmentations were performed on T2w -FLAIR and contrast-enhanced T1w images. Therapy response assessment and determination of PFS were performed according to response assessment in neuro oncology (RANO) criteria using clinical follow-up data with a median observation time of 9.2 mo (range, 1.6-40.8) and compared to CEST MRI metrics. Statistical testing included receiver operating characteristic analyses, Mann-Whitney-U-test, Kaplan-Meier analyses, and logrank-test. RESULTS MTconst (AUC = 0.79, p < 0.01) showed a stronger association with RANO response assessment compared to PeakAreaAPT (AUC = 0.71, p = 0.02) and MTRRex MT (AUC = 0.71, p = 0.02), and enabled differentiation of participants with pseudoprogression (n = 8) from those with true progression (AUC = 0.79, p = 0.02). Furthermore, MTconst (HR = 3.04, p = 0.01), PeakAreaAPT (HR = 0.39, p = 0.03), and APTwasym (HR = 2.63, p = 0.02) were associated with PFS. MTRRex APT was not associated with any outcome. CONCLUSION MTconst , PeakAreaAPT, and APTwasym imaging predict clinical outcome by means of progression-free survival. Furthermore, MTconst enables differentiation of radiation-induced pseudoprogression from disease progression. Therefore, the assessed metrics may have synergistic potential for supporting clinical decision making during follow-up of patients with glioma.
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Affiliation(s)
- Florian Kroh
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Department of Physics and Astronomy, University of Heidelberg, Heidelberg, Germany
| | | | - Johannes Breitling
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Srdjan Maksimovic
- Division of Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Laila König
- Department of Radiation Oncology, University Hospital Heidelberg, Heidelberg, Germany
| | - Sebastian Adeberg
- Department of Radiation Oncology, University Hospital Heidelberg, Heidelberg, Germany
- Faculty of Medicine, University of Heidelberg, Heidelberg, Germany
| | | | - Andreas Unterberg
- Faculty of Medicine, University of Heidelberg, Heidelberg, Germany
- Department of Neurosurgery, Heidelberg, Germany
| | - Martin Bendszus
- Faculty of Medicine, University of Heidelberg, Heidelberg, Germany
- Department of Neuroradiology, University Hospital Heidelberg, Heidelberg, Germany
| | - Wolfgang Wick
- Faculty of Medicine, University of Heidelberg, Heidelberg, Germany
- Department of Neurology, University Hospital Heidelberg, Heidelberg, Germany
| | - Peter Bachert
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Department of Physics and Astronomy, University of Heidelberg, Heidelberg, Germany
| | - Jürgen Debus
- Department of Radiation Oncology, University Hospital Heidelberg, Heidelberg, Germany
- Faculty of Medicine, University of Heidelberg, Heidelberg, Germany
- Clinical Cooperation Unit Radiation Oncology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Mark E Ladd
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Department of Physics and Astronomy, University of Heidelberg, Heidelberg, Germany
- Faculty of Medicine, University of Heidelberg, Heidelberg, Germany
| | - Heinz-Peter Schlemmer
- Division of Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Faculty of Medicine, University of Heidelberg, Heidelberg, Germany
| | - Andreas Korzowski
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Steffen Goerke
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Daniel Paech
- Division of Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Department of Neuroradiology, University Hospital Bonn, Bonn, Germany
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14
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Knebel Doeberitz NV, Kroh F, Breitling J, König L, Maksimovic S, Graß S, Adeberg S, Scherer M, Unterberg A, Bendszus M, Wick W, Bachert P, Debus J, Ladd ME, Schlemmer HP, Korzowski A, Goerke S, Paech D. CEST Imaging of the APT and ssMT predict the overall survival of patients with glioma at the first follow-up after completion of radiotherapy at 3T. Radiother Oncol 2023; 184:109694. [PMID: 37150450 DOI: 10.1016/j.radonc.2023.109694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 04/27/2023] [Accepted: 04/28/2023] [Indexed: 05/09/2023]
Abstract
BACKGROUND AND PURPOSE Outcome prediction of patients with glioma early after the completion of radiotherapy represents a major clinical challenge. Previously, the prognostic value of chemical exchange saturation transfer (CEST) imaging has been demonstrated in patients with newly diagnosed glioma. The objective of this study was to assess the potential of amide proton transfer (APT)-, relayed nuclear Overhauser effect (rNOE)- and semi-solid magnetization transfer (ssMT)-imaging according to Zhou et al. (APTwasym), Goerke et al. (MTRRexAPT, MTRRexNOE and MTRRexMT) and Mehrabian et al. (PeakAreaAPT, PeakAreaNOE and MTconst) for the prognostication of the overall survival (OS) of patients with glioma at the first follow-up after the completion of radiotherapy. MATERIALS AND METHODS 49 of 72 participants with diffuse glioma, who underwent CEST MRI at 3T between July 2018 and December 2021 4 to 6 weeks after the completion of radiotherapy, were analyzed. Contrast-enhancing tumor (CE) and whole tumor (WT) volumes were segmented on T2w-FLAIR and contrast-enhanced T1w images. Kaplan-Meier analysis and logrank-test were used for statistical analyses. RESULTS APTw imaging demonstrated the strongest association with OS (HR=4.66, p<0.001). The MTconst (HR=2.54, p=0.044) was associated with the OS of participants with residual contrast-enhancing glioma tissue, whilst the MTRRexAPT (HR=2.44, p=0.056) showed a trend in this sub-cohort. The MTRRexNOE, MTRRexMT and PeakAreaNOE were not associated with survival. CONCLUSION Imaging of the APT and ssMT at the first follow-up 4 to 6 weeks after the completion of radiotherapy at 3T were associated with the overall survival of patients with glioma.
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Affiliation(s)
| | - Florian Kroh
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany; Department of Physics and Astronomy, University of Heidelberg, Heidelberg, Germany
| | - Johannes Breitling
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Laila König
- Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany
| | - Srdjan Maksimovic
- Division of Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Svenja Graß
- Division of Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Sebastian Adeberg
- Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany; Faculty of Medicine, University of Heidelberg, Heidelberg, Germany
| | - Moritz Scherer
- Department of Neurosurgery, University Hospital Heidelberg, Heidelberg, Germany
| | - Andreas Unterberg
- Department of Neurosurgery, University Hospital Heidelberg, Heidelberg, Germany; Faculty of Medicine, University of Heidelberg, Heidelberg, Germany
| | - Martin Bendszus
- Department of Neuroradiology, University Hospital Heidelberg, Heidelberg, Germany; Faculty of Medicine, University of Heidelberg, Heidelberg, Germany
| | - Wolfgang Wick
- Department of Neurology, University Hospital Heidelberg, Heidelberg, Germany; Faculty of Medicine, University of Heidelberg, Heidelberg, Germany
| | - Peter Bachert
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany; Department of Physics and Astronomy, University of Heidelberg, Heidelberg, Germany
| | - Jürgen Debus
- Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany; Clinical Cooperation Unit Radiation Oncology, German Cancer Research Center (DKFZ), Heidelberg, Germany; Faculty of Medicine, University of Heidelberg, Heidelberg, Germany
| | - Mark E Ladd
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany; Department of Physics and Astronomy, University of Heidelberg, Heidelberg, Germany; Faculty of Medicine, University of Heidelberg, Heidelberg, Germany
| | - Heinz-Peter Schlemmer
- Division of Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany; Faculty of Medicine, University of Heidelberg, Heidelberg, Germany
| | - Andreas Korzowski
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Steffen Goerke
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Daniel Paech
- Division of Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany; Department of Neuroradiology, University Hospital Bonn, Bonn, Germany.
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15
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Jäschke D, Steiner KM, Chang DI, Claaßen J, Uslar E, Thieme A, Gerwig M, Pfaffenrot V, Hulst T, Gussew A, Maderwald S, Göricke SL, Minnerop M, Ladd ME, Reichenbach JR, Timmann D, Deistung A. Age-related differences of cerebellar cortex and nuclei: MRI findings in healthy controls and its application to spinocerebellar ataxia (SCA6) patients. Neuroimage 2023; 270:119950. [PMID: 36822250 DOI: 10.1016/j.neuroimage.2023.119950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 02/06/2023] [Accepted: 02/15/2023] [Indexed: 02/24/2023] Open
Abstract
Understanding cerebellar alterations due to healthy aging provides a reference point against which pathological findings in late-onset disease, for example spinocerebellar ataxia type 6 (SCA6), can be contrasted. In the present study, we investigated the impact of aging on the cerebellar nuclei and cerebellar cortex in 109 healthy controls (age range: 16 - 78 years) using 3 Tesla magnetic resonance imaging (MRI). Findings were compared with 25 SCA6 patients (age range: 38 - 78 years). A subset of 16 SCA6 (included: 14) patients and 50 controls (included: 45) received an additional MRI scan at 7 Tesla and were re-scanned after one year. MRI included T1-weighted, T2-weighted FLAIR, and multi-echo T2*-weighted imaging. The T2*-weighted phase images were converted to quantitative susceptibility maps (QSM). Since the cerebellar nuclei are characterized by elevated iron content with respect to their surroundings, two independent raters manually outlined them on the susceptibility maps. T1-weighted images acquired at 3T were utilized to automatically identify the cerebellar gray matter (GM) volume. Linear correlations revealed significant atrophy of the cerebellum due to tissue loss of cerebellar cortical GM in healthy controls with increasing age. Reduction of the cerebellar GM was substantially stronger in SCA6 patients. The volume of the dentate nuclei did not exhibit a significant relationship with age, at least in the age range between 18 and 78 years, whereas mean susceptibilities of the dentate nuclei increased with age. As previously shown, the dentate nuclei volumes were smaller and magnetic susceptibilities were lower in SCA6 patients compared to age- and sex-matched controls. The significant dentate volume loss in SCA6 patients could also be confirmed with 7T MRI. Linear mixed effects models and individual paired t-tests accounting for multiple comparisons revealed no statistical significant change in volume and susceptibility of the dentate nuclei after one year in neither patients nor controls. Importantly, dentate volumes were more sensitive to differentiate between SCA6 (Cohen's d = 3.02) and matched controls than the cerebellar cortex volume (d = 2.04). In addition to age-related decline of the cerebellar cortex and atrophy in SCA6 patients, age-related increase of susceptibility of the dentate nuclei was found in controls, whereas dentate volume and susceptibility was significantly decreased in SCA6 patients. Because no significant changes of any of these parameters was found at follow-up, these measures do not allow to monitor disease progression at short intervals.
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Affiliation(s)
- Dominik Jäschke
- Department of Neurology and Center for Translational Neuro- and Behavioral Sciences (C-TNBS), Essen University Hospital, University of Duisburg-Essen, Essen 45147, Germany; Department of Radiology and Nuclear Medicine, University Hospital Basel, Basel 4031, Switzerland
| | - Katharina M Steiner
- Department of Neurology and Center for Translational Neuro- and Behavioral Sciences (C-TNBS), Essen University Hospital, University of Duisburg-Essen, Essen 45147, Germany; LVR-Hospital Essen, Department of Psychiatry and Psychotherapy, Medical Faculty, University of Duisburg-Essen, Essen 45147, Germany
| | - Dae-In Chang
- Department of Neurology and Center for Translational Neuro- and Behavioral Sciences (C-TNBS), Essen University Hospital, University of Duisburg-Essen, Essen 45147, Germany; Clinic for Psychiatry, Psychotherapy and Preventive Medicine, LWL-University Hospital of the Ruhr-University Bochum, Bochum 44791, Germany
| | - Jens Claaßen
- Department of Neurology and Center for Translational Neuro- and Behavioral Sciences (C-TNBS), Essen University Hospital, University of Duisburg-Essen, Essen 45147, Germany; Fachklinik für Neurologie, MEDICLIN Klinik Reichshof, Reichshof-Eckenhagen 51580, Germany
| | - Ellen Uslar
- Department of Neurology and Center for Translational Neuro- and Behavioral Sciences (C-TNBS), Essen University Hospital, University of Duisburg-Essen, Essen 45147, Germany
| | - Andreas Thieme
- Department of Neurology and Center for Translational Neuro- and Behavioral Sciences (C-TNBS), Essen University Hospital, University of Duisburg-Essen, Essen 45147, Germany
| | - Marcus Gerwig
- Department of Neurology and Center for Translational Neuro- and Behavioral Sciences (C-TNBS), Essen University Hospital, University of Duisburg-Essen, Essen 45147, Germany
| | - Viktor Pfaffenrot
- Erwin L. Hahn Institute for Magnetic Resonance Imaging, University of Duisburg-Essen, Essen 45141, Germany
| | - Thomas Hulst
- Department of Neurology and Center for Translational Neuro- and Behavioral Sciences (C-TNBS), Essen University Hospital, University of Duisburg-Essen, Essen 45147, Germany; Erasmus University College, Rotterdam 3011 HP, the Netherlands
| | - Alexander Gussew
- University Clinic and Outpatient Clinic for Radiology, Department for Radiation Medicine, University Hospital Halle (Saale), Ernst-Grube-Str. 40, Halle (Saale) 06120, Germany
| | - Stefan Maderwald
- Erwin L. Hahn Institute for Magnetic Resonance Imaging, University of Duisburg-Essen, Essen 45141, Germany
| | - Sophia L Göricke
- Institute of Diagnostic and Interventional Neuroradiology, Essen University Hospital, University of Duisburg-Essen, Essen 45141, Germany
| | - Martina Minnerop
- Institute of Neuroscience and Medicine (INM-1), Research Centre Juelich, Juelich 52425, Germany; Department of Neurology, Center for Movement Disorders and Neuromodulation, Medical Faculty and University Hospital Düsseldorf, Heinrich-Heine University Düsseldorf, Düsseldorf 40225, Germany; Institute of Clinical Neuroscience and Medical Psychology, Medical Faculty and University Hospital Düsseldorf, Heinrich-Heine University Düsseldorf, Düsseldorf 40225, Germany
| | - Mark E Ladd
- Erwin L. Hahn Institute for Magnetic Resonance Imaging, University of Duisburg-Essen, Essen 45141, Germany; Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg 69120, Germany; Faculty of Physics and Astronomy and Faculty of Medicine, Heidelberg University, Heidelberg 69120, Germany
| | - Jürgen R Reichenbach
- Medical Physics Group, Institute of Diagnostic and Interventional Radiology, Jena University Hospital, Jena 07743, Germany
| | - Dagmar Timmann
- Department of Neurology and Center for Translational Neuro- and Behavioral Sciences (C-TNBS), Essen University Hospital, University of Duisburg-Essen, Essen 45147, Germany; Erwin L. Hahn Institute for Magnetic Resonance Imaging, University of Duisburg-Essen, Essen 45141, Germany
| | - Andreas Deistung
- Department of Neurology and Center for Translational Neuro- and Behavioral Sciences (C-TNBS), Essen University Hospital, University of Duisburg-Essen, Essen 45147, Germany; University Clinic and Outpatient Clinic for Radiology, Department for Radiation Medicine, University Hospital Halle (Saale), Ernst-Grube-Str. 40, Halle (Saale) 06120, Germany; Medical Physics Group, Institute of Diagnostic and Interventional Radiology, Jena University Hospital, Jena 07743, Germany.
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16
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Ladd ME, Quick HH, Speck O, Bock M, Doerfler A, Forsting M, Hennig J, Ittermann B, Möller HE, Nagel AM, Niendorf T, Remy S, Schaeffter T, Scheffler K, Schlemmer HP, Schmitter S, Schreiber L, Shah NJ, Stöcker T, Uder M, Villringer A, Weiskopf N, Zaiss M, Zaitsev M. Germany's journey toward 14 Tesla human magnetic resonance. MAGMA 2023; 36:191-210. [PMID: 37029886 PMCID: PMC10140098 DOI: 10.1007/s10334-023-01085-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 03/23/2023] [Accepted: 03/27/2023] [Indexed: 04/09/2023]
Abstract
Multiple sites within Germany operate human MRI systems with magnetic fields either at 7 Tesla or 9.4 Tesla. In 2013, these sites formed a network to facilitate and harmonize the research being conducted at the different sites and make this technology available to a larger community of researchers and clinicians not only within Germany, but also worldwide. The German Ultrahigh Field Imaging (GUFI) network has defined a strategic goal to establish a 14 Tesla whole-body human MRI system as a national research resource in Germany as the next progression in magnetic field strength. This paper summarizes the history of this initiative, the current status, the motivation for pursuing MR imaging and spectroscopy at such a high magnetic field strength, and the technical and funding challenges involved. It focuses on the scientific and science policy process from the perspective in Germany, and is not intended to be a comprehensive systematic review of the benefits and technical challenges of higher field strengths.
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Affiliation(s)
- Mark E Ladd
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120, Heidelberg, Germany.
- Faculty of Medicine, Heidelberg University, Heidelberg, Germany.
- Faculty of Physics and Astronomy, Heidelberg University, Heidelberg, Germany.
- Erwin L. Hahn Institute for MRI, University of Duisburg-Essen, Essen, Germany.
| | - Harald H Quick
- Erwin L. Hahn Institute for MRI, University of Duisburg-Essen, Essen, Germany
- High-Field and Hybrid MR Imaging, University Hospital Essen, Essen, Germany
| | - Oliver Speck
- Department of Biomedical Magnetic Resonance, Otto von Guericke University Magdeburg, Magdeburg, Germany
- German Center for Neurodegenerative Diseases (DZNE), Magdeburg, Germany
- Center for Behavioural Brain Sciences, Magdeburg, Germany
- Leibniz Institute for Neurobiology (LIN), Magdeburg, Germany
| | - Michael Bock
- Division of Medical Physics, Department of Diagnostic and Interventional Radiology, Faculty of Medicine, Medical Center, University of Freiburg, Freiburg, Germany
| | - Arnd Doerfler
- Department of Neuroradiology, University Hospital Erlangen, Friedrich-Alexander University Erlangen-Nuremberg (FAU), Erlangen, Germany
| | - Michael Forsting
- Institute of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, Germany
| | - Jürgen Hennig
- Division of Medical Physics, Department of Diagnostic and Interventional Radiology, Faculty of Medicine, Medical Center, University of Freiburg, Freiburg, Germany
| | - Bernd Ittermann
- Medical Physics and Metrological Information Technology, Physikalisch-Technische Bundesanstalt (PTB), Berlin, Germany
| | - Harald E Möller
- Methods and Development Group Nuclear Magnetic Resonance, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - Armin M Nagel
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120, Heidelberg, Germany
- Institute of Radiology, University Hospital Erlangen, Friedrich-Alexander University Erlangen-Nuremberg (FAU), Erlangen, Germany
| | - Thoralf Niendorf
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Stefan Remy
- German Center for Neurodegenerative Diseases (DZNE), Magdeburg, Germany
- Leibniz Institute for Neurobiology (LIN), Magdeburg, Germany
| | - Tobias Schaeffter
- Medical Physics and Metrological Information Technology, Physikalisch-Technische Bundesanstalt (PTB), Berlin, Germany
| | - Klaus Scheffler
- Magnetic Resonance Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany
- Department of Biomedical Magnetic Resonance, University of Tübingen, Tübingen, Germany
| | | | - Sebastian Schmitter
- Medical Physics and Metrological Information Technology, Physikalisch-Technische Bundesanstalt (PTB), Berlin, Germany
| | - Laura Schreiber
- Department of Cardiovascular Imaging, Comprehensive Heart Failure Center, University Hospital Würzburg, Würzburg, Germany
| | - N Jon Shah
- Institute of Neuroscience and Medicine - 4, Forschungszentrum Jülich, Jülich, Germany
| | - Tony Stöcker
- MR Physics, German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Michael Uder
- Institute of Radiology, University Hospital Erlangen, Friedrich-Alexander University Erlangen-Nuremberg (FAU), Erlangen, Germany
| | - Arno Villringer
- Department of Neurology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - Nikolaus Weiskopf
- Department of Neurophysics, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
- Felix Bloch Institute for Solid State Physics, Faculty of Physics and Earth Sciences, Leipzig University, Leipzig, Germany
| | - Moritz Zaiss
- Department of Neuroradiology, University Hospital Erlangen, Friedrich-Alexander University Erlangen-Nuremberg (FAU), Erlangen, Germany
| | - Maxim Zaitsev
- Division of Medical Physics, Department of Diagnostic and Interventional Radiology, Faculty of Medicine, Medical Center, University of Freiburg, Freiburg, Germany
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17
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Straub S, El-Sanosy E, Emmerich J, Sandig FL, Ladd ME, Schlemmer HP. Quantitative magnetic resonance imaging biomarkers for cortical pathology in multiple sclerosis at 7 T. NMR Biomed 2023; 36:e4847. [PMID: 36259249 DOI: 10.1002/nbm.4847] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 10/08/2022] [Accepted: 10/12/2022] [Indexed: 06/16/2023]
Abstract
Substantial cortical gray matter tissue damage, which correlates with clinical disease severity, has been revealed in multiple sclerosis (MS) using advanced magnetic resonance imaging (MRI) methods at 3 T and the use of ultra-high field, as well as in histopathology studies. While clinical assessment mainly focuses on lesions using T 1 - and T 2 -weighted MRI, quantitative MRI (qMRI) methods are capable of uncovering subtle microstructural changes. The aim of this ultra-high field study is to extract possible future MR biomarkers for the quantitative evaluation of regional cortical pathology. Because of their sensitivity to iron, myelin, and in part specifically to cortical demyelination, T 1 , T 2 , R 2 * , and susceptibility mapping were performed including two novel susceptibility markers; in addition, cortical thickness as well as the volumes of 34 cortical regions were computed. Data were acquired in 20 patients and 16 age- and sex-matched healthy controls. In 18 cortical regions, large to very large effect sizes (Cohen's d ≥ 1) and statistically significant differences in qMRI values between patients and controls were revealed compared with only four regions when using more standard MR measures, namely, volume and cortical thickness. Moreover, a decrease in all susceptibility contrasts ( χ , χ + , χ - ) and R 2 * values indicates that the role of cortical demyelination might outweigh inflammatory processes in the form of iron accumulation in cortical MS pathology, and might also indicate iron loss. A significant association between susceptibility contrasts as well as R 2 * of the caudal middle frontal gyrus and disease duration was found (adjusted R2 : 0.602, p = 0.0011). Quantitative MRI parameters might be more sensitive towards regional cortical pathology compared with the use of conventional markers only and therefore may play a role in early detection of tissue damage in MS in the future.
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Affiliation(s)
- Sina Straub
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Faculty of Medicine, Heidelberg University, Heidelberg, Germany
| | - Edris El-Sanosy
- Division Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Julian Emmerich
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Frederik L Sandig
- Division Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Mark E Ladd
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Faculty of Medicine, Heidelberg University, Heidelberg, Germany
- Faculty of Physics and Astronomy, Heidelberg University, Heidelberg, Germany
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18
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Heiss R, Weber MA, Balbach E, Schmitt R, Rehnitz C, Laqmani A, Sternberg A, Ellermann JJ, Nagel AM, Ladd ME, Englbrecht M, Arkudas A, Horch R, Guermazi A, Uder M, Roemer FW. Clinical Application of Ultrahigh-Field-Strength Wrist MRI: A Multireader 3-T and 7-T Comparison Study. Radiology 2023; 307:e220753. [PMID: 36625744 DOI: 10.1148/radiol.220753] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Background Ultrahigh-field-strength MRI at 7 T may permit superior visualization of noninflammatory wrist pathologic conditions, particularly due to its high signal-to-noise ratio compared with the clinical standard of 3 T, but direct comparison studies are lacking. Purpose To compare the subjective image quality of 3-T and 7-T ultrahigh-field-strength wrist MRI through semiquantitative scoring of multiple joint tissues in a multireader study. Materials and Methods In this prospective study, healthy controls and participants with chronic wrist pain underwent 3-T and 7-T MRI (coronal T1-weighted turbo spin-echo [TSE], coronal fat-suppressed proton-density [PD]-weighted TSE, transversal T2-weighted TSE) on the same day, from July 2018 to June 2019. Images were scored by seven musculoskeletal radiologists. The overall image quality, presence of artifacts, homogeneity of fat suppression, and visualization of cartilage, the triangular fibrocartilage complex (TFCC), and scapholunate and lunotriquetral ligaments were semiquantitatively assessed. Pairwise differences between 3 T and 7 T were assessed using the Wilcoxon signed-rank test. Interreader reliability was determined using the Fleiss kappa. Results In total, 25 healthy controls (mean age, 25 years ± 4 [SD]; 13 women) and 25 participants with chronic wrist pain (mean age, 39 years ± 16; 14 men) were included. Overall image quality (P = .002) and less presence of artifacts at PD-weighted fat-suppressed MRI were superior at 7 T. T1- and T2-weighted MRI were superior at 3 T (both P < .001), as was fat suppression (P < .001). Visualization of cartilage was superior at 7 T (P < .001), while visualization of the TFCC (P < .001) and scapholunate (P = .048) and lunotriquetral (P = .04) ligaments was superior at 3 T. Interreader reliability showed slight to substantial agreement for the detected pathologic conditions (κ = 0.20-0.64). Conclusion A 7-T MRI of the wrist had potential advantages over 3-T MRI, particularly in cartilage assessment. However, superiority was not shown for all parameters; for example, visualization of the triangular fibrocartilage complex and wrist ligaments was superior at 3 T. © RSNA, 2023 Supplemental material is available for this article.
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Affiliation(s)
- Rafael Heiss
- Department of Radiology (R. Heiss, E.B., A.M.N., M.U., F.W.R.) and Department of Plastic and Hand Surgery and Laboratory for Tissue Engineering and Regenerative Medicine (A.A., R. Horch), University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Maximiliansplatz 3, 91054 Erlangen, Germany; Institute of Diagnostic and Interventional Radiology, Pediatric Radiology and Neuroradiology, University Medical Center Rostock, Rostock, Germany (M.A.W.); Department of Radiology, Ludwig Maximilian University of Munich, Munich, Germany (R.S.); Diagnostic and Interventional Radiology, University Hospital Heidelberg, Heidelberg, Germany (C.R.); Department of Diagnostic and Interventional Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany (A.L.); Medizinisches Versorgungszentrum am Rotes Kreuz Krankenhaus, Bremen, Germany (A.S.); University of Minnesota Medical School, Minneapolis, Minnesota (J.J.E.); Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany (A.M.N., M.E.L.); Statscoach, Eckental, Germany (M.E.); VA Boston Healthcare System, West Roxbury, Mass (A.G.); and Boston University School of Medicine, Boston, Mass (M.U., F.W.R.)
| | - Marc-André Weber
- Department of Radiology (R. Heiss, E.B., A.M.N., M.U., F.W.R.) and Department of Plastic and Hand Surgery and Laboratory for Tissue Engineering and Regenerative Medicine (A.A., R. Horch), University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Maximiliansplatz 3, 91054 Erlangen, Germany; Institute of Diagnostic and Interventional Radiology, Pediatric Radiology and Neuroradiology, University Medical Center Rostock, Rostock, Germany (M.A.W.); Department of Radiology, Ludwig Maximilian University of Munich, Munich, Germany (R.S.); Diagnostic and Interventional Radiology, University Hospital Heidelberg, Heidelberg, Germany (C.R.); Department of Diagnostic and Interventional Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany (A.L.); Medizinisches Versorgungszentrum am Rotes Kreuz Krankenhaus, Bremen, Germany (A.S.); University of Minnesota Medical School, Minneapolis, Minnesota (J.J.E.); Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany (A.M.N., M.E.L.); Statscoach, Eckental, Germany (M.E.); VA Boston Healthcare System, West Roxbury, Mass (A.G.); and Boston University School of Medicine, Boston, Mass (M.U., F.W.R.)
| | - Eva Balbach
- Department of Radiology (R. Heiss, E.B., A.M.N., M.U., F.W.R.) and Department of Plastic and Hand Surgery and Laboratory for Tissue Engineering and Regenerative Medicine (A.A., R. Horch), University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Maximiliansplatz 3, 91054 Erlangen, Germany; Institute of Diagnostic and Interventional Radiology, Pediatric Radiology and Neuroradiology, University Medical Center Rostock, Rostock, Germany (M.A.W.); Department of Radiology, Ludwig Maximilian University of Munich, Munich, Germany (R.S.); Diagnostic and Interventional Radiology, University Hospital Heidelberg, Heidelberg, Germany (C.R.); Department of Diagnostic and Interventional Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany (A.L.); Medizinisches Versorgungszentrum am Rotes Kreuz Krankenhaus, Bremen, Germany (A.S.); University of Minnesota Medical School, Minneapolis, Minnesota (J.J.E.); Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany (A.M.N., M.E.L.); Statscoach, Eckental, Germany (M.E.); VA Boston Healthcare System, West Roxbury, Mass (A.G.); and Boston University School of Medicine, Boston, Mass (M.U., F.W.R.)
| | - Rainer Schmitt
- Department of Radiology (R. Heiss, E.B., A.M.N., M.U., F.W.R.) and Department of Plastic and Hand Surgery and Laboratory for Tissue Engineering and Regenerative Medicine (A.A., R. Horch), University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Maximiliansplatz 3, 91054 Erlangen, Germany; Institute of Diagnostic and Interventional Radiology, Pediatric Radiology and Neuroradiology, University Medical Center Rostock, Rostock, Germany (M.A.W.); Department of Radiology, Ludwig Maximilian University of Munich, Munich, Germany (R.S.); Diagnostic and Interventional Radiology, University Hospital Heidelberg, Heidelberg, Germany (C.R.); Department of Diagnostic and Interventional Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany (A.L.); Medizinisches Versorgungszentrum am Rotes Kreuz Krankenhaus, Bremen, Germany (A.S.); University of Minnesota Medical School, Minneapolis, Minnesota (J.J.E.); Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany (A.M.N., M.E.L.); Statscoach, Eckental, Germany (M.E.); VA Boston Healthcare System, West Roxbury, Mass (A.G.); and Boston University School of Medicine, Boston, Mass (M.U., F.W.R.)
| | - Christoph Rehnitz
- Department of Radiology (R. Heiss, E.B., A.M.N., M.U., F.W.R.) and Department of Plastic and Hand Surgery and Laboratory for Tissue Engineering and Regenerative Medicine (A.A., R. Horch), University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Maximiliansplatz 3, 91054 Erlangen, Germany; Institute of Diagnostic and Interventional Radiology, Pediatric Radiology and Neuroradiology, University Medical Center Rostock, Rostock, Germany (M.A.W.); Department of Radiology, Ludwig Maximilian University of Munich, Munich, Germany (R.S.); Diagnostic and Interventional Radiology, University Hospital Heidelberg, Heidelberg, Germany (C.R.); Department of Diagnostic and Interventional Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany (A.L.); Medizinisches Versorgungszentrum am Rotes Kreuz Krankenhaus, Bremen, Germany (A.S.); University of Minnesota Medical School, Minneapolis, Minnesota (J.J.E.); Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany (A.M.N., M.E.L.); Statscoach, Eckental, Germany (M.E.); VA Boston Healthcare System, West Roxbury, Mass (A.G.); and Boston University School of Medicine, Boston, Mass (M.U., F.W.R.)
| | - Azien Laqmani
- Department of Radiology (R. Heiss, E.B., A.M.N., M.U., F.W.R.) and Department of Plastic and Hand Surgery and Laboratory for Tissue Engineering and Regenerative Medicine (A.A., R. Horch), University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Maximiliansplatz 3, 91054 Erlangen, Germany; Institute of Diagnostic and Interventional Radiology, Pediatric Radiology and Neuroradiology, University Medical Center Rostock, Rostock, Germany (M.A.W.); Department of Radiology, Ludwig Maximilian University of Munich, Munich, Germany (R.S.); Diagnostic and Interventional Radiology, University Hospital Heidelberg, Heidelberg, Germany (C.R.); Department of Diagnostic and Interventional Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany (A.L.); Medizinisches Versorgungszentrum am Rotes Kreuz Krankenhaus, Bremen, Germany (A.S.); University of Minnesota Medical School, Minneapolis, Minnesota (J.J.E.); Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany (A.M.N., M.E.L.); Statscoach, Eckental, Germany (M.E.); VA Boston Healthcare System, West Roxbury, Mass (A.G.); and Boston University School of Medicine, Boston, Mass (M.U., F.W.R.)
| | - Andreas Sternberg
- Department of Radiology (R. Heiss, E.B., A.M.N., M.U., F.W.R.) and Department of Plastic and Hand Surgery and Laboratory for Tissue Engineering and Regenerative Medicine (A.A., R. Horch), University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Maximiliansplatz 3, 91054 Erlangen, Germany; Institute of Diagnostic and Interventional Radiology, Pediatric Radiology and Neuroradiology, University Medical Center Rostock, Rostock, Germany (M.A.W.); Department of Radiology, Ludwig Maximilian University of Munich, Munich, Germany (R.S.); Diagnostic and Interventional Radiology, University Hospital Heidelberg, Heidelberg, Germany (C.R.); Department of Diagnostic and Interventional Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany (A.L.); Medizinisches Versorgungszentrum am Rotes Kreuz Krankenhaus, Bremen, Germany (A.S.); University of Minnesota Medical School, Minneapolis, Minnesota (J.J.E.); Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany (A.M.N., M.E.L.); Statscoach, Eckental, Germany (M.E.); VA Boston Healthcare System, West Roxbury, Mass (A.G.); and Boston University School of Medicine, Boston, Mass (M.U., F.W.R.)
| | - Jutta J Ellermann
- Department of Radiology (R. Heiss, E.B., A.M.N., M.U., F.W.R.) and Department of Plastic and Hand Surgery and Laboratory for Tissue Engineering and Regenerative Medicine (A.A., R. Horch), University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Maximiliansplatz 3, 91054 Erlangen, Germany; Institute of Diagnostic and Interventional Radiology, Pediatric Radiology and Neuroradiology, University Medical Center Rostock, Rostock, Germany (M.A.W.); Department of Radiology, Ludwig Maximilian University of Munich, Munich, Germany (R.S.); Diagnostic and Interventional Radiology, University Hospital Heidelberg, Heidelberg, Germany (C.R.); Department of Diagnostic and Interventional Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany (A.L.); Medizinisches Versorgungszentrum am Rotes Kreuz Krankenhaus, Bremen, Germany (A.S.); University of Minnesota Medical School, Minneapolis, Minnesota (J.J.E.); Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany (A.M.N., M.E.L.); Statscoach, Eckental, Germany (M.E.); VA Boston Healthcare System, West Roxbury, Mass (A.G.); and Boston University School of Medicine, Boston, Mass (M.U., F.W.R.)
| | - Armin M Nagel
- Department of Radiology (R. Heiss, E.B., A.M.N., M.U., F.W.R.) and Department of Plastic and Hand Surgery and Laboratory for Tissue Engineering and Regenerative Medicine (A.A., R. Horch), University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Maximiliansplatz 3, 91054 Erlangen, Germany; Institute of Diagnostic and Interventional Radiology, Pediatric Radiology and Neuroradiology, University Medical Center Rostock, Rostock, Germany (M.A.W.); Department of Radiology, Ludwig Maximilian University of Munich, Munich, Germany (R.S.); Diagnostic and Interventional Radiology, University Hospital Heidelberg, Heidelberg, Germany (C.R.); Department of Diagnostic and Interventional Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany (A.L.); Medizinisches Versorgungszentrum am Rotes Kreuz Krankenhaus, Bremen, Germany (A.S.); University of Minnesota Medical School, Minneapolis, Minnesota (J.J.E.); Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany (A.M.N., M.E.L.); Statscoach, Eckental, Germany (M.E.); VA Boston Healthcare System, West Roxbury, Mass (A.G.); and Boston University School of Medicine, Boston, Mass (M.U., F.W.R.)
| | - Mark E Ladd
- Department of Radiology (R. Heiss, E.B., A.M.N., M.U., F.W.R.) and Department of Plastic and Hand Surgery and Laboratory for Tissue Engineering and Regenerative Medicine (A.A., R. Horch), University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Maximiliansplatz 3, 91054 Erlangen, Germany; Institute of Diagnostic and Interventional Radiology, Pediatric Radiology and Neuroradiology, University Medical Center Rostock, Rostock, Germany (M.A.W.); Department of Radiology, Ludwig Maximilian University of Munich, Munich, Germany (R.S.); Diagnostic and Interventional Radiology, University Hospital Heidelberg, Heidelberg, Germany (C.R.); Department of Diagnostic and Interventional Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany (A.L.); Medizinisches Versorgungszentrum am Rotes Kreuz Krankenhaus, Bremen, Germany (A.S.); University of Minnesota Medical School, Minneapolis, Minnesota (J.J.E.); Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany (A.M.N., M.E.L.); Statscoach, Eckental, Germany (M.E.); VA Boston Healthcare System, West Roxbury, Mass (A.G.); and Boston University School of Medicine, Boston, Mass (M.U., F.W.R.)
| | - Matthias Englbrecht
- Department of Radiology (R. Heiss, E.B., A.M.N., M.U., F.W.R.) and Department of Plastic and Hand Surgery and Laboratory for Tissue Engineering and Regenerative Medicine (A.A., R. Horch), University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Maximiliansplatz 3, 91054 Erlangen, Germany; Institute of Diagnostic and Interventional Radiology, Pediatric Radiology and Neuroradiology, University Medical Center Rostock, Rostock, Germany (M.A.W.); Department of Radiology, Ludwig Maximilian University of Munich, Munich, Germany (R.S.); Diagnostic and Interventional Radiology, University Hospital Heidelberg, Heidelberg, Germany (C.R.); Department of Diagnostic and Interventional Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany (A.L.); Medizinisches Versorgungszentrum am Rotes Kreuz Krankenhaus, Bremen, Germany (A.S.); University of Minnesota Medical School, Minneapolis, Minnesota (J.J.E.); Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany (A.M.N., M.E.L.); Statscoach, Eckental, Germany (M.E.); VA Boston Healthcare System, West Roxbury, Mass (A.G.); and Boston University School of Medicine, Boston, Mass (M.U., F.W.R.)
| | - Andreas Arkudas
- Department of Radiology (R. Heiss, E.B., A.M.N., M.U., F.W.R.) and Department of Plastic and Hand Surgery and Laboratory for Tissue Engineering and Regenerative Medicine (A.A., R. Horch), University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Maximiliansplatz 3, 91054 Erlangen, Germany; Institute of Diagnostic and Interventional Radiology, Pediatric Radiology and Neuroradiology, University Medical Center Rostock, Rostock, Germany (M.A.W.); Department of Radiology, Ludwig Maximilian University of Munich, Munich, Germany (R.S.); Diagnostic and Interventional Radiology, University Hospital Heidelberg, Heidelberg, Germany (C.R.); Department of Diagnostic and Interventional Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany (A.L.); Medizinisches Versorgungszentrum am Rotes Kreuz Krankenhaus, Bremen, Germany (A.S.); University of Minnesota Medical School, Minneapolis, Minnesota (J.J.E.); Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany (A.M.N., M.E.L.); Statscoach, Eckental, Germany (M.E.); VA Boston Healthcare System, West Roxbury, Mass (A.G.); and Boston University School of Medicine, Boston, Mass (M.U., F.W.R.)
| | - Raymund Horch
- Department of Radiology (R. Heiss, E.B., A.M.N., M.U., F.W.R.) and Department of Plastic and Hand Surgery and Laboratory for Tissue Engineering and Regenerative Medicine (A.A., R. Horch), University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Maximiliansplatz 3, 91054 Erlangen, Germany; Institute of Diagnostic and Interventional Radiology, Pediatric Radiology and Neuroradiology, University Medical Center Rostock, Rostock, Germany (M.A.W.); Department of Radiology, Ludwig Maximilian University of Munich, Munich, Germany (R.S.); Diagnostic and Interventional Radiology, University Hospital Heidelberg, Heidelberg, Germany (C.R.); Department of Diagnostic and Interventional Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany (A.L.); Medizinisches Versorgungszentrum am Rotes Kreuz Krankenhaus, Bremen, Germany (A.S.); University of Minnesota Medical School, Minneapolis, Minnesota (J.J.E.); Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany (A.M.N., M.E.L.); Statscoach, Eckental, Germany (M.E.); VA Boston Healthcare System, West Roxbury, Mass (A.G.); and Boston University School of Medicine, Boston, Mass (M.U., F.W.R.)
| | - Ali Guermazi
- Department of Radiology (R. Heiss, E.B., A.M.N., M.U., F.W.R.) and Department of Plastic and Hand Surgery and Laboratory for Tissue Engineering and Regenerative Medicine (A.A., R. Horch), University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Maximiliansplatz 3, 91054 Erlangen, Germany; Institute of Diagnostic and Interventional Radiology, Pediatric Radiology and Neuroradiology, University Medical Center Rostock, Rostock, Germany (M.A.W.); Department of Radiology, Ludwig Maximilian University of Munich, Munich, Germany (R.S.); Diagnostic and Interventional Radiology, University Hospital Heidelberg, Heidelberg, Germany (C.R.); Department of Diagnostic and Interventional Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany (A.L.); Medizinisches Versorgungszentrum am Rotes Kreuz Krankenhaus, Bremen, Germany (A.S.); University of Minnesota Medical School, Minneapolis, Minnesota (J.J.E.); Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany (A.M.N., M.E.L.); Statscoach, Eckental, Germany (M.E.); VA Boston Healthcare System, West Roxbury, Mass (A.G.); and Boston University School of Medicine, Boston, Mass (M.U., F.W.R.)
| | - Michael Uder
- Department of Radiology (R. Heiss, E.B., A.M.N., M.U., F.W.R.) and Department of Plastic and Hand Surgery and Laboratory for Tissue Engineering and Regenerative Medicine (A.A., R. Horch), University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Maximiliansplatz 3, 91054 Erlangen, Germany; Institute of Diagnostic and Interventional Radiology, Pediatric Radiology and Neuroradiology, University Medical Center Rostock, Rostock, Germany (M.A.W.); Department of Radiology, Ludwig Maximilian University of Munich, Munich, Germany (R.S.); Diagnostic and Interventional Radiology, University Hospital Heidelberg, Heidelberg, Germany (C.R.); Department of Diagnostic and Interventional Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany (A.L.); Medizinisches Versorgungszentrum am Rotes Kreuz Krankenhaus, Bremen, Germany (A.S.); University of Minnesota Medical School, Minneapolis, Minnesota (J.J.E.); Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany (A.M.N., M.E.L.); Statscoach, Eckental, Germany (M.E.); VA Boston Healthcare System, West Roxbury, Mass (A.G.); and Boston University School of Medicine, Boston, Mass (M.U., F.W.R.)
| | - Frank W Roemer
- Department of Radiology (R. Heiss, E.B., A.M.N., M.U., F.W.R.) and Department of Plastic and Hand Surgery and Laboratory for Tissue Engineering and Regenerative Medicine (A.A., R. Horch), University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Maximiliansplatz 3, 91054 Erlangen, Germany; Institute of Diagnostic and Interventional Radiology, Pediatric Radiology and Neuroradiology, University Medical Center Rostock, Rostock, Germany (M.A.W.); Department of Radiology, Ludwig Maximilian University of Munich, Munich, Germany (R.S.); Diagnostic and Interventional Radiology, University Hospital Heidelberg, Heidelberg, Germany (C.R.); Department of Diagnostic and Interventional Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany (A.L.); Medizinisches Versorgungszentrum am Rotes Kreuz Krankenhaus, Bremen, Germany (A.S.); University of Minnesota Medical School, Minneapolis, Minnesota (J.J.E.); Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany (A.M.N., M.E.L.); Statscoach, Eckental, Germany (M.E.); VA Boston Healthcare System, West Roxbury, Mass (A.G.); and Boston University School of Medicine, Boston, Mass (M.U., F.W.R.)
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Orzada S, Akash S, Fiedler TM, Kratzer FJ, Ladd ME. An investigation into the dependence of virtual observation point‐based specific absorption rate calculation complexity on number of channels. Magn Reson Med 2022; 89:469-476. [DOI: 10.1002/mrm.29434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 07/13/2022] [Accepted: 08/10/2022] [Indexed: 11/11/2022]
Affiliation(s)
- Stephan Orzada
- Medical Physics in Radiology German Cancer Research Center (DKFZ) Heidelberg Germany
- Erwin L. Hahn Institute for MRI University Duisburg‐Essen Essen Germany
- Radiation Oncology University Hospital Heidelberg Heidelberg Germany
| | - Safi Akash
- Medical Physics in Radiology German Cancer Research Center (DKFZ) Heidelberg Germany
| | - Thomas M. Fiedler
- Medical Physics in Radiology German Cancer Research Center (DKFZ) Heidelberg Germany
| | - Fabian J. Kratzer
- Medical Physics in Radiology German Cancer Research Center (DKFZ) Heidelberg Germany
| | - Mark E. Ladd
- Medical Physics in Radiology German Cancer Research Center (DKFZ) Heidelberg Germany
- Erwin L. Hahn Institute for MRI University Duisburg‐Essen Essen Germany
- Faculty of Physics and Astronomy Heidelberg University Heidelberg Germany
- Faculty of Medicine Heidelberg University Heidelberg Germany
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20
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Frass-Kriegl R, Broche LM, Ginefri JC, Ladd ME, Roat S, Sarracanie M, Winkler SAS, Laistler E. Editorial: Innovations in MR hardware from ultra-low to ultra-high field. Front Phys 2022; 10:1015289. [PMID: 37564749 PMCID: PMC10414785 DOI: 10.3389/fphy.2022.1015289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/12/2023]
Affiliation(s)
- Roberta Frass-Kriegl
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Lionel Marc Broche
- Aberdeen Biomedical Imaging Centre, University of Aberdeen, Aberdeen, United Kingdom
| | - Jean-Christophe Ginefri
- Université Paris-Saclay, CEA, CNRS, Inserm, BioMaps, Service Hospitalier Frédéric Joliot, Orsay, France
| | - Mark E. Ladd
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Sigrun Roat
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Mathieu Sarracanie
- Center for Adaptable MRI Technology, Department of Biomedical Engineering, University of Basel, Allschwil, Switzerland
| | | | - Elmar Laistler
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
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21
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Stelter JK, Ladd ME, Fiedler TM. Numerical comparison of local transceiver arrays of fractionated dipoles and microstrip antennas for body imaging at 7 T. NMR Biomed 2022; 35:e4722. [PMID: 35226966 DOI: 10.1002/nbm.4722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 01/28/2022] [Accepted: 02/23/2022] [Indexed: 06/14/2023]
Abstract
Longitudinally orientated dipoles and microstrip antennas have both demonstrated superior results as RF transmit elements for body imaging at 7 T MRI, and are as of today the most commonly used transmit elements. In this study, the performances of the two antenna concepts were compared for use in local RF antenna arrays by numerical simulations. Antenna elements investigated are the fractionated dipole and the microstrip line with meander structures. Phantom simulations with a single antenna element were performed and evaluated with regard to specific absorption rate (SAR) efficiency in the center of the subject. Simulations of array configurations with 8 and 16 elements were performed with anatomical body models. Both antenna elements were combined with a loop coil to compare hybrid configurations. Singular value decomposition of the B1+ fields, RF shimming, and calculation of the voxel-wise power and SAR efficiencies were performed in regions of interest with varying sizes to evaluate the transmit performance. The signal-to-noise ratio (SNR) was evaluated to estimate the receive performance. Simulated data show similar transmit profiles for the two antenna types in the center of the phantom (penetration depth > 20 mm). For body imaging, no considerable differences were determined for the different antenna configurations with regard to the transmit performance. Results show the advantage of 16 transmit channels compared with today's commonly used 8-channel systems (minimum RF shimming excitation error of 4.7% (4.3%) versus 2.7% (2.8%) for the 8-channel and 16-channel configurations with the microstrip antennas in a (5 cm)3 cube in the center of a male (female) body model). Highest SNR is achieved for the 16-channel configuration with fractionated dipoles. The combination of either fractionated dipoles or microstrip antennas with loop coils is more favorable with regard to the transmit performance compared with only increasing the number of elements.
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Affiliation(s)
- Jonathan K Stelter
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Mark E Ladd
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Erwin L. Hahn Institute for MRI, University Duisburg-Essen, Essen, Germany
- Faculty of Physics and Astronomy, Heidelberg University, Heidelberg, Germany
- Faculty of Medicine, Heidelberg University, Heidelberg, Germany
| | - Thomas M Fiedler
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
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22
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Breitling J, Korzowski A, Kempa N, Boyd PS, Paech D, Schlemmer HP, Ladd ME, Bachert P, Goerke S. Motion correction for three-dimensional chemical exchange saturation transfer imaging without direct water saturation artifacts. NMR Biomed 2022; 35:e4720. [PMID: 35233847 DOI: 10.1002/nbm.4720] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 11/25/2021] [Accepted: 02/22/2022] [Indexed: 06/14/2023]
Abstract
In chemical exchange saturation transfer (CEST) MRI, motion correction is compromised by the drastically changing image contrast at different frequency offsets, particularly at the direct water saturation. In this study, a simple extension for conventional image registration algorithms is proposed, enabling robust and accurate motion correction of CEST-MRI data. The proposed method uses weighted averaging of motion parameters from a conventional rigid image registration to identify and mitigate erroneously misaligned images. Functionality of the proposed method was verified by ground truth datasets generated from 10 three-dimensional in vivo measurements at 3 T with simulated realistic random rigid motion patterns and noise. Performance was assessed using two different criteria: the maximum image misalignment as a measure for the robustness against direct water saturation artifacts, and the spectral error as a measure of the overall accuracy. For both criteria, the proposed method achieved the best scores compared with two motion-correction algorithms specifically developed to handle the varying contrasts in CEST-MRI. Compared with a straightforward linear interpolation of the motion parameters at frequency offsets close to the direct water saturation, the proposed method offers better performance in the absence of artifacts. The proposed method for motion correction in CEST-MRI allows identification and mitigation of direct water saturation artifacts that occur with conventional image registration algorithms. The resulting improved robustness and accuracy enable reliable motion correction, which is particularly crucial for an automated and carefree evaluation of spectral CEST-MRI data, e.g., for large patient cohorts or in clinical routines.
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Affiliation(s)
- Johannes Breitling
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Andreas Korzowski
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Neele Kempa
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Faculty of Physics and Astronomy, University of Heidelberg, Heidelberg, Germany
| | - Philip S Boyd
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Faculty of Physics and Astronomy, University of Heidelberg, Heidelberg, Germany
| | - Daniel Paech
- Division of Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | | | - Mark E Ladd
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Faculty of Physics and Astronomy, University of Heidelberg, Heidelberg, Germany
- Faculty of Medicine, University of Heidelberg, Heidelberg, Germany
| | - Peter Bachert
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Faculty of Physics and Astronomy, University of Heidelberg, Heidelberg, Germany
| | - Steffen Goerke
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
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23
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Loi L, Goerke S, Zimmermann F, Korzowski A, Meissner JE, Breitling J, Schott S, Bachert P, Ladd ME, Schlemmer HP, Bickelhaupt S, Paech D. Assessing the influence of the menstrual cycle on APT CEST-MRI in the human breast. Magn Reson Imaging 2022; 91:24-31. [PMID: 35550841 DOI: 10.1016/j.mri.2022.05.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Revised: 05/05/2022] [Accepted: 05/05/2022] [Indexed: 10/18/2022]
Abstract
PURPOSE In fibroglandular breast tissue, conventional dynamic contrast-enhanced MR-mammography is known to be affected by water content changes during the menstrual cycle. Likewise, amide proton transfer (APT) chemical exchange saturation transfer (CEST)-MRI might be inherently prone to the menstrual cycle, as CEST signals are indirectly detected via the water signal. The purpose of this study was to investigate the influence of the menstrual cycle on APT CEST-MRI in fibroglandular breast tissue. METHOD Ten healthy premenopausal women (19-34 years) were included in this IRB approved prospective study and examined twice during their menstrual cycle. Examination one and two were performed during the first half (day 2-8) and the second half (day 15-21) of the menstrual cycle, respectively. As a reference for the APT signal in malignant breast tumor tissue, previously reported data of nine breast cancer patients were included in this study. CEST-MRI (B1 = 0.7μT) was performed on a 7 T whole-body scanner followed by a multi-Lorentzian fit analysis. The APT signal was corrected for B0/B1-field inhomogeneities, fat signal contribution, and relaxation effects of the water signal and evaluated in the fibroglandular breast tissue. Intra-individual APT signal differences between examination one and two were compared using the Wilcoxon signed-rank test. The level of significance was set at p < 0.05. RESULTS The APT signal showed no significant difference in the fibroglandular breast tissue of healthy premenopausal volunteers throughout the menstrual cycle (p = 1.00) (examination 1 vs. examination 2: mean and standard deviation = 3.24 ± 0.68%Hz vs. 3.30 ± 0.73%Hz, median and IQR = 3.36%Hz and 0.87%Hz vs. 3.38%Hz and 0.71%Hz). CONCLUSION The present study provides an important basis for the clinical application of APT CEST-MRI as an additional contrast mechanism in MR-mammography, as menstrual cycle-related APT signal fluctuations seem to be negligible compared to the APT signal increase in breast cancer tissue.
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Affiliation(s)
- Lisa Loi
- German Cancer Research Center, Department of Radiology, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany; Faculty of Medicine, University of Heidelberg, Im Neuenheimer Feld 672, 69120 Heidelberg, Germany
| | - Steffen Goerke
- German Cancer Research Center, Department of Medical Physics in Radiology, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Ferdinand Zimmermann
- German Cancer Research Center, Department of Medical Physics in Radiology, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Andreas Korzowski
- German Cancer Research Center, Department of Medical Physics in Radiology, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Jan-Eric Meissner
- German Cancer Research Center, Department of Medical Physics in Radiology, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Johannes Breitling
- German Cancer Research Center, Department of Medical Physics in Radiology, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Sarah Schott
- University Hospital Heidelberg, Department of Gynecology and Obstetrics, Im Neuenheimer Feld 440, 69120 Heidelberg, Germany
| | - Peter Bachert
- German Cancer Research Center, Department of Medical Physics in Radiology, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany; Faculty of Physics and Astronomy, University of Heidelberg, Im Neuenheimer Feld 226, 69120 Heidelberg, Germany
| | - Mark E Ladd
- Faculty of Medicine, University of Heidelberg, Im Neuenheimer Feld 672, 69120 Heidelberg, Germany; German Cancer Research Center, Department of Medical Physics in Radiology, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany; Faculty of Physics and Astronomy, University of Heidelberg, Im Neuenheimer Feld 226, 69120 Heidelberg, Germany
| | - Heinz-Peter Schlemmer
- German Cancer Research Center, Department of Radiology, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany; Faculty of Medicine, University of Heidelberg, Im Neuenheimer Feld 672, 69120 Heidelberg, Germany
| | - Sebastian Bickelhaupt
- German Cancer Research Center, Department of Radiology, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany; German Cancer Research Center, Junior Group Medical Imaging and Radiology - Cancer Prevention, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Daniel Paech
- German Cancer Research Center, Department of Radiology, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany.
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Fiedler TM, Orzada S, Flöser M, Rietsch SHG, Schmidt S, Stelter JK, Wittrich M, Quick HH, Bitz AK, Ladd ME. Performance and safety assessment of an integrated transmit array for body imaging at 7 T under consideration of specific absorption rate, tissue temperature, and thermal dose. NMR Biomed 2022; 35:e4656. [PMID: 34962689 DOI: 10.1002/nbm.4656] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 10/18/2021] [Accepted: 11/05/2021] [Indexed: 05/12/2023]
Abstract
In this study, the performance of an integrated body-imaging array for 7 T with 32 radiofrequency (RF) channels under consideration of local specific absorption rate (SAR), tissue temperature, and thermal dose limits was evaluated and the imaging performance was compared with a clinical 3 T body coil. Thirty-two transmit elements were placed in three rings between the bore liner and RF shield of the gradient coil. Slice-selective RF pulse optimizations for B1 shimming and spokes were performed for differently oriented slices in the body under consideration of realistic constraints for power and local SAR. To improve the B1+ homogeneity, safety assessments based on temperature and thermal dose were performed to possibly allow for higher input power for the pulse optimization than permissible with SAR limits. The results showed that using two spokes, the 7 T array outperformed the 3 T birdcage in all the considered regions of interest. However, a significantly higher SAR or lower duty cycle at 7 T is necessary in some cases to achieve similar B1+ homogeneity as at 3 T. The homogeneity in up to 50 cm-long coronal slices can particularly benefit from the high RF shim performance provided by the 32 RF channels. The thermal dose approach increases the allowable input power and the corresponding local SAR, in one example up to 100 W/kg, without limiting the exposure time necessary for an MR examination. In conclusion, the integrated antenna array at 7 T enables a clinical workflow for body imaging and comparable imaging performance to a conventional 3 T clinical body coil.
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Affiliation(s)
- Thomas M Fiedler
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Stephan Orzada
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Martina Flöser
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Stefan H G Rietsch
- Erwin L. Hahn Institute for MRI, University Duisburg-Essen, Essen, Germany
- High-Field and Hybrid MR Imaging, University Hospital Essen, Essen, Germany
| | - Simon Schmidt
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Faculty of Physics and Astronomy, University of Heidelberg, Heidelberg, Germany
| | - Jonathan K Stelter
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Marco Wittrich
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Harald H Quick
- Erwin L. Hahn Institute for MRI, University Duisburg-Essen, Essen, Germany
- High-Field and Hybrid MR Imaging, University Hospital Essen, Essen, Germany
| | - Andreas K Bitz
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Electromagnetic Theory and Applied Mathematics, Faculty of Electrical Engineering and Information Technology, FH Aachen - University of Applied Sciences, Aachen, Germany
| | - Mark E Ladd
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Erwin L. Hahn Institute for MRI, University Duisburg-Essen, Essen, Germany
- Faculty of Physics and Astronomy, University of Heidelberg, Heidelberg, Germany
- Faculty of Medicine, University of Heidelberg, Heidelberg, Germany
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25
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Franke VL, Breitling J, Ladd ME, Bachert P, Korzowski A. 31 P MRSI at 7 T enables high-resolution volumetric mapping of the intracellular magnesium ion content in human lower leg muscles. Magn Reson Med 2022; 88:511-523. [PMID: 35381111 DOI: 10.1002/mrm.29231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 02/21/2022] [Accepted: 02/22/2022] [Indexed: 11/06/2022]
Abstract
PURPOSE The non-invasive determination of the free magnesium ion concentration ([Mg2+ free ]) using 31 P MRSI in vivo is of interest in research on various pathologies, e.g. diabetes. The purpose of this study was to demonstrate the potential of 31 P MRSI at 7 T to enable volumetric, high-resolution mapping of [Mg2+ free ]. METHODS 3D 31 P MRSI datasets from the lower leg of three healthy volunteers were acquired at B0 = 7 T with a nominal spatial resolution of (8 × 8 × 16) mm3 in 56 min. Volumetric [Mg2+ free ] maps were calculated based on the quantified local chemical shift difference between the α- and β-resonance of adenosine triphosphate (ATP) considering also local pH values. Mean [Mg2+ free ] values from three different muscle groups were compared. To demonstrate the potential of reducing the measurement time, the analysis was repeated on the acquired MRSI data retrospectively reconstructed with fewer averages. RESULTS The generated [Mg2+ free ] maps revealed local differences, and mean [Mg2+ free ] values of (1.08 ± 0.03) mM were found in the tibialis anterior, (0.91 ± 0.04) mM in the soleus and (0.98 ± 0.03) mM in the gastrocnemius medialis. The time-reduced 28-min scan resulted in comparable [Mg2+ free ] maps, and mean values being in agreement with the values from the 56-min scan. CONCLUSION 31 P MRSI at 7 T enables volumetric, high-resolution mapping of free magnesium ion content in human lower leg muscles. The measurement time of the 31 P MRSI acquisition can be reduced to 28 min, opening the potential to apply volumetric [Mg2+ free ] mapping for the investigation of pathologies with altered magnesium homeostasis.
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Affiliation(s)
- Vanessa L Franke
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany.,Faculty of Physics and Astronomy, University of Heidelberg, Heidelberg, Germany
| | - Johannes Breitling
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Mark E Ladd
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany.,Faculty of Physics and Astronomy, University of Heidelberg, Heidelberg, Germany.,Faculty of Medicine, University of Heidelberg, Heidelberg, Germany
| | - Peter Bachert
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany.,Faculty of Physics and Astronomy, University of Heidelberg, Heidelberg, Germany
| | - Andreas Korzowski
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
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26
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Sato T, Matsushige T, Chen B, Gembruch O, Dammann P, Jabbarli R, Forsting M, Junker A, Maderwald S, Quick HH, Ladd ME, Sure U, Wrede KH. Correlation Between Thrombus Signal Intensity and Aneurysm Wall Thickness in Partially Thrombosed Intracranial Aneurysms Using 7T Magnetization-Prepared Rapid Acquisition Gradient Echo Magnetic Resonance Imaging. Front Neurol 2022; 13:758126. [PMID: 35250805 PMCID: PMC8894319 DOI: 10.3389/fneur.2022.758126] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 01/17/2022] [Indexed: 11/13/2022] Open
Abstract
Objective The objective of this study is to investigate the relationship between the thrombus signal intensity and aneurysm wall thickness in partially thrombosed intracranial aneurysms in vivo with magnetization-prepared rapid acquisition gradient echo (MPRAGE) taken using 7T magnetic resonance imaging (MRI) and correlate the findings to wall instability. Methods Sixteen partially thrombosed intracranial aneurysms were evaluated using a 7T whole-body MR system with nonenhanced MPRAGE. To normalize the thrombus signal intensity, its highest signal intensity was compared to that of the anterior corpus callosum of the same subject, and the signal intensity ratio was calculated. The correlation between the thrombus signal intensity ratio and the thickness of the aneurysm wall was analyzed. Furthermore, aneurysmal histopathological specimens from six tissue samples were compared with radiological findings to detect any correlation. Results The mean thrombus signal intensity ratio was 0.57 (standard error of the mean [SEM] 0.06, range 0.25–1.01). The mean thickness of the aneurysm wall was 1.25 (SEM 0.08, range 0.84–1.55) mm. The thrombus signal intensity ratio significantly correlated with the aneurysm wall thickness (p < 0.01). The aneurysm walls with the high thrombus signal intensity ratio were significantly thicker. In histopathological examinations, three patients with a hypointense thrombus had fewer macrophages infiltrating the thrombus and a thin degenerated aneurysmal wall. In contrast, three patients with a hyperintense thrombus had abundant macrophages infiltrating the thrombus. Conclusion The thrombus signal intensity ratio in partially thrombosed intracranial aneurysms correlated with aneurysm wall thickness and histologic features, indicating wall instability.
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Affiliation(s)
- Taku Sato
- Department of Neurosurgery, University Hospital Essen, University Duisburg-Essen, Essen, Germany
- Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany
- Department of Neurosurgery, Fukushima Medical University, Fukushima, Japan
- *Correspondence: Taku Sato
| | - Toshinori Matsushige
- Department of Neurosurgery, University Hospital Essen, University Duisburg-Essen, Essen, Germany
- Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany
- Department of Neurosurgery, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
- Department of Neurosurgery and Interventional Neuroradiology, Hiroshima City Asa Citizens Hospital, Hiroshima, Japan
| | - Bixia Chen
- Department of Neurosurgery, University Hospital Essen, University Duisburg-Essen, Essen, Germany
- Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany
| | - Oliver Gembruch
- Department of Neurosurgery, University Hospital Essen, University Duisburg-Essen, Essen, Germany
- Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany
| | - Philipp Dammann
- Department of Neurosurgery, University Hospital Essen, University Duisburg-Essen, Essen, Germany
- Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany
| | - Ramazan Jabbarli
- Department of Neurosurgery, University Hospital Essen, University Duisburg-Essen, Essen, Germany
| | - Michael Forsting
- Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, University Duisburg-Essen, Essen, Germany
| | - Andreas Junker
- Institute of Neuropathology, University Hospital Essen, University Duisburg-Essen, Essen, Germany
| | - Stefan Maderwald
- Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany
| | - Harald H. Quick
- Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany
- High Field and Hybrid MR Imaging, University Hospital Essen, University Duisburg-Essen, Essen, Germany
| | - Mark E. Ladd
- Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Faculty of Physics and Astronomy and Faculty of Medicine, University of Heidelberg, Heidelberg, Germany
| | - Ulrich Sure
- Department of Neurosurgery, University Hospital Essen, University Duisburg-Essen, Essen, Germany
| | - Karsten H. Wrede
- Department of Neurosurgery, University Hospital Essen, University Duisburg-Essen, Essen, Germany
- Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany
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Lingl JP, Wunderlich A, Goerke S, Paech D, Ladd ME, Liebig P, Pala A, Kim SY, Braun M, Schmitz BL, Beer M, Rosskopf J. The Value of APTw CEST MRI in Routine Clinical Assessment of Human Brain Tumor Patients at 3T. Diagnostics (Basel) 2022; 12:diagnostics12020490. [PMID: 35204583 PMCID: PMC8871436 DOI: 10.3390/diagnostics12020490] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 02/08/2022] [Accepted: 02/10/2022] [Indexed: 12/10/2022] Open
Abstract
Background. With fast-growing evidence in literature for clinical applications of chemical exchange saturation transfer (CEST) magnetic resonance imaging (MRI), this prospective study aimed at applying amide proton transfer-weighted (APTw) CEST imaging in a clinical setting to assess its diagnostic potential in differentiation of intracranial tumors at 3 tesla (T). Methods. Using the asymmetry magnetization transfer ratio (MTRasym) analysis, CEST signals were quantitatively investigated in the tumor areas and in a similar sized region of the normal-appearing white matter (NAWM) on the contralateral hemisphere of 27 patients with intracranial tumors. Area under curve (AUC) analyses were used and results were compared to perfusion-weighted imaging (PWI). Results. Using APTw CEST, contrast-enhancing tumor areas showed significantly higher APTw CEST metrics than contralateral NAWM (AUC = 0.82; p < 0.01). In subgroup analyses of each tumor entity vs. NAWM, statistically significant effects were yielded for glioblastomas (AUC = 0.96; p < 0.01) and for meningiomas (AUC = 1.0; p < 0.01) but not for lymphomas as well as metastases (p > 0.05). PWI showed results comparable to APTw CEST in glioblastoma (p < 0.01). Conclusions. This prospective study confirmed the high diagnostic potential of APTw CEST imaging in a routine clinical setting to differentiate brain tumors.
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Affiliation(s)
- Julia P. Lingl
- Department of Radiology, Ulm University, Albert-Einstein-Allee 23, 89081 Ulm, Germany; (J.P.L.); (A.W.); (S.Y.K.); (M.B.); (B.L.S.); (M.B.)
| | - Arthur Wunderlich
- Department of Radiology, Ulm University, Albert-Einstein-Allee 23, 89081 Ulm, Germany; (J.P.L.); (A.W.); (S.Y.K.); (M.B.); (B.L.S.); (M.B.)
| | - Steffen Goerke
- German Cancer Research Center (DKFZ), Department of Medical Physics in Radiology, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany; (S.G.); (M.E.L.)
| | - Daniel Paech
- German Cancer Research Center (DKFZ), Division of Radiology, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany;
- Department of Neuroradiology, Venusberg-Campus 1, Bonn University, 53127 Bonn, Germany
| | - Mark E. Ladd
- German Cancer Research Center (DKFZ), Department of Medical Physics in Radiology, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany; (S.G.); (M.E.L.)
- Faculty of Medicine, University of Heidelberg, Im Neuenheimer Feld 672, 69120 Heidelberg, Germany
- Faculty of Physics and Astronomy, University of Heidelberg, Im Neuenheimer Feld 226, 69120 Heidelberg, Germany
| | - Patrick Liebig
- Siemens Healthcare GmbH, Henkestraße 127, 91052 Erlangen, Germany;
| | - Andrej Pala
- Department of Neurosurgery, Bezirkskrankenhaus Guenzburg, Lindenallee 2, 89312 Guenzburg, Germany;
| | - Soung Yung Kim
- Department of Radiology, Ulm University, Albert-Einstein-Allee 23, 89081 Ulm, Germany; (J.P.L.); (A.W.); (S.Y.K.); (M.B.); (B.L.S.); (M.B.)
- Section of Neuroradiology, Bezirkskrankenhaus Guenzburg, Lindenallee 2, 89312 Guenzburg, Germany
| | - Michael Braun
- Department of Radiology, Ulm University, Albert-Einstein-Allee 23, 89081 Ulm, Germany; (J.P.L.); (A.W.); (S.Y.K.); (M.B.); (B.L.S.); (M.B.)
- Section of Neuroradiology, Bezirkskrankenhaus Guenzburg, Lindenallee 2, 89312 Guenzburg, Germany
| | - Bernd L. Schmitz
- Department of Radiology, Ulm University, Albert-Einstein-Allee 23, 89081 Ulm, Germany; (J.P.L.); (A.W.); (S.Y.K.); (M.B.); (B.L.S.); (M.B.)
- Section of Neuroradiology, Bezirkskrankenhaus Guenzburg, Lindenallee 2, 89312 Guenzburg, Germany
| | - Meinrad Beer
- Department of Radiology, Ulm University, Albert-Einstein-Allee 23, 89081 Ulm, Germany; (J.P.L.); (A.W.); (S.Y.K.); (M.B.); (B.L.S.); (M.B.)
| | - Johannes Rosskopf
- Department of Radiology, Ulm University, Albert-Einstein-Allee 23, 89081 Ulm, Germany; (J.P.L.); (A.W.); (S.Y.K.); (M.B.); (B.L.S.); (M.B.)
- Section of Neuroradiology, Bezirkskrankenhaus Guenzburg, Lindenallee 2, 89312 Guenzburg, Germany
- Correspondence:
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Straub S, Stiegeler J, El-Sanosy E, Bendszus M, Ladd ME, Schneider TM. A novel gradient echo data based vein segmentation algorithm and its application for the detection of regional cerebral differences in venous susceptibility. Neuroimage 2022; 250:118931. [PMID: 35085764 DOI: 10.1016/j.neuroimage.2022.118931] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 01/14/2022] [Accepted: 01/23/2022] [Indexed: 11/18/2022] Open
Abstract
Accurate segmentation of cerebral venous vasculature from gradient echo data is of central importance in several areas of neuroimaging such as for the susceptibility-based assessment of brain oxygenation or planning of electrode placement in deep brain stimulation. In this study, a vein segmentation algorithm for single- and multi-echo gradient echo data is proposed. First, susceptibility maps, true susceptibility-weighted images, and, in the multi-echo case, R2* maps were generated from the gradient echo data. These maps were filtered with an inverted Hamming filter to suppress background contrast as well as artifacts from field inhomogeneities at the brain boundaries. A shearlet-based scale-wise representation was generated to calculate a vesselness function and to generate segmentations based on local thresholding. The accuracy of the proposed algorithm was evaluated for different echo times and image resolutions using a manually generated reference segmentation and two vein segmentation algorithms (Frangi vesselness-based, recursive vesselness filter) as a reference with the Dice and Cohen's coefficients as well as the modified Hausdorff distance. The Frangi-based and recursive vesselness filter methods were significantly outperformed with regard to all error metrics. Applying the algorithm, susceptibility differences likely related to differences in blood oxygenation between superficial and deep venous territories could be demonstrated.
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Affiliation(s)
- Sina Straub
- Divison of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Janis Stiegeler
- Divison of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany; Faculty of Physics and Astronomy, University of Heidelberg, Heidelberg, Germany
| | - Edris El-Sanosy
- Divison of Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Martin Bendszus
- Department of Neuroradiology, University of Heidelberg, Im Neuenheimer Feld 400, Heidelberg 69120, Germany
| | - Mark E Ladd
- Divison of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany; Faculty of Physics and Astronomy, University of Heidelberg, Heidelberg, Germany; Faculty of Medicine, University of Heidelberg, Heidelberg, Germany
| | - Till M Schneider
- Department of Neuroradiology, University of Heidelberg, Im Neuenheimer Feld 400, Heidelberg 69120, Germany.
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Korzowski A, Weckesser N, Franke VL, Breitling J, Goerke S, Schlemmer HP, Ladd ME, Bachert P, Paech D. Mapping an Extended Metabolic Profile of Gliomas Using High-Resolution 31P MRSI at 7T. Front Neurol 2022; 12:735071. [PMID: 35002914 PMCID: PMC8733158 DOI: 10.3389/fneur.2021.735071] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 11/08/2021] [Indexed: 11/13/2022] Open
Abstract
Phosphorus magnetic resonance spectroscopic imaging (31P MRSI) is of particular interest for investigations of patients with brain tumors as it enables to non-invasively assess altered energy and phospholipid metabolism in vivo. However, the limited sensitivity of 31P MRSI hampers its broader application at clinical field strengths. This study aimed to identify the additional value of 31P MRSI in patients with glioma at ultra-high B0 = 7T, where the increase in signal-to-noise ratio may foster its applicability for clinical research. High-quality, 3D 31P MRSI datasets with an effective voxel size of 5.7 ml were acquired from the brains of seven patients with newly diagnosed glioma. An optimized quantification model was implemented to reliably extract an extended metabolic profile, including low-concentrated metabolites such as extracellular inorganic phosphate, nicotinamide adenine dinucleotide [NAD(H)], and uridine diphosphoglucose (UDPG), which may act as novel tumor markers; a background signal was extracted as well, which affected measures of phosphomonoesters beneficially. Application of this model to the MRSI datasets yielded high-resolution maps of 12 different 31P metabolites, showing clear metabolic differences between white matter (WM) and gray matter, and between healthy and tumor tissues. Moreover, differences between tumor compartments in patients with high-grade glioma (HGG), i.e., gadolinium contrast-enhancing/necrotic regions (C+N) and peritumoral edema, could also be suggested from these maps. In the group of patients with HGG, the most significant changes in metabolite intensities were observed in C+N compared to WM, i.e., for phosphocholine +340%, UDPG +54%, glycerophosphoethanolamine −45%, and adenosine-5′-triphosphate −29%. Furthermore, a prominent signal from mobile phospholipids appeared in C+N. In the group of patients with low-grade glioma, only the NAD(H) intensity changed significantly by −28% in the tumor compared to WM. Besides the potential of 31P MRSI at 7T to provide novel insights into the biochemistry of gliomas in vivo, the attainable spatial resolutions improve the interpretability of 31P metabolite intensities obtained from malignant tissues, particularly when only subtle differences compared to healthy tissues are expected. In conclusion, this pilot study demonstrates that 31P MRSI at 7T has potential value for the clinical research of glioma.
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Affiliation(s)
- Andreas Korzowski
- Department of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Nina Weckesser
- Department of Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany.,Faculty of Medicine, University of Heidelberg, Heidelberg, Germany
| | - Vanessa L Franke
- Department of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany.,Faculty of Physics and Astronomy, University of Heidelberg, Heidelberg, Germany
| | - Johannes Breitling
- Department of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Steffen Goerke
- Department of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | | | - Mark E Ladd
- Department of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany.,Faculty of Medicine, University of Heidelberg, Heidelberg, Germany.,Faculty of Physics and Astronomy, University of Heidelberg, Heidelberg, Germany
| | - Peter Bachert
- Department of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany.,Faculty of Physics and Astronomy, University of Heidelberg, Heidelberg, Germany
| | - Daniel Paech
- Department of Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
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30
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Boyd PS, Breitling J, Korzowski A, Zaiss M, Franke VL, Mueller-Decker K, Glinka A, Ladd ME, Bachert P, Goerke S. Mapping intracellular pH in tumors using amide and guanidyl CEST-MRI at 9.4 T. Magn Reson Med 2021; 87:2436-2452. [PMID: 34958684 DOI: 10.1002/mrm.29133] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 11/26/2021] [Accepted: 12/07/2021] [Indexed: 12/11/2022]
Abstract
PURPOSE In principle, non-invasive mapping of the intracellular pH (pHi ) in vivo is possible using endogenous chemical exchange saturation transfer (CEST)-MRI of the amide and guanidyl signals. However, the application for cancer imaging is still impeded, as current state-of-the-art approaches do not allow for simultaneous compensation of concomitant effects that vary within tumors. In this study, we present a novel method for absolute pHi mapping using endogenous CEST-MRI, which simultaneously compensates for concentration changes, superimposing CEST signals, magnetization transfer contrast, and spillover dilution. THEORY AND METHODS Compensation of the concomitant effects was achieved by a ratiometric approach (i.e. the ratio of one CEST signal at different B1 ) in combination with the relaxation-compensated inverse magnetization transfer ratio MTRRex and a separate first-order polynomial-Lorentzian fit of the amide and guanidyl signals at 9.4 T. Calibration of pH values was accomplished using in vivo-like model suspensions from porcine brain lysates. Applicability of the presented method in vivo was demonstrated in n = 19 tumor-bearing mice. RESULTS In porcine brain lysates, measurement of pH was feasible over a broad range of physiologically relevant pH values of 6.2 to 8.0, while being independent of changes in concentration. A median pHi of approximately 7.2 was found in the lesions of 19 tumor-bearing mice. CONCLUSION The presented method enables non-invasive mapping of absolute pHi values in tumors using CEST-MRI, which was so far prevented by concomitant effects. Consequently, pre-clinical studies on pHi changes in tumors are possible allowing the assessment of pHi in vivo as a biomarker for cancer diagnosis or treatment monitoring.
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Affiliation(s)
- Philip S Boyd
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany.,Faculty of Physics and Astronomy, University of Heidelberg, Heidelberg, Germany
| | - Johannes Breitling
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Andreas Korzowski
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Moritz Zaiss
- Division of Neuroradiology in Radiological Institute, University Hospital of Erlangen, Erlangen, Germany
| | - Vanessa L Franke
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany.,Faculty of Physics and Astronomy, University of Heidelberg, Heidelberg, Germany
| | - Karin Mueller-Decker
- Core Facility Tumor Models (Center for Preclinical Research), German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Andrey Glinka
- Division of Molecular Embryology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Mark E Ladd
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany.,Faculty of Physics and Astronomy, University of Heidelberg, Heidelberg, Germany.,Faculty of Medicine, University of Heidelberg, Heidelberg, Germany
| | - Peter Bachert
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany.,Faculty of Physics and Astronomy, University of Heidelberg, Heidelberg, Germany
| | - Steffen Goerke
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
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Paech D, Regnery S, Platt T, Behl NGR, Weckesser N, Windisch P, Deike-Hofmann K, Wick W, Bendszus M, Rieken S, König L, Ladd ME, Schlemmer HP, Debus J, Adeberg S. Assessment of Sodium MRI at 7 Tesla as Predictor of Therapy Response and Survival in Glioblastoma Patients. Front Neurosci 2021; 15:782516. [PMID: 34924945 PMCID: PMC8671745 DOI: 10.3389/fnins.2021.782516] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Accepted: 11/09/2021] [Indexed: 11/13/2022] Open
Abstract
The purpose of this work was to prospectively investigate sodium (23Na) MRI at 7 Tesla (T) as predictor of therapy response and survival in patients with glioblastoma (GBM). Thus, 20 GBM patients underwent 23Na MRI at 7T before, immediately after and 6 weeks after chemoradiotherapy (CRT). The median tissue sodium concentration (TSC) inside the whole tumor excluding necrosis was determined. Initial response to CRT was assessed employing the updated response assessment in neuro-oncology working group (RANO) criteria. Clinical parameters, baseline TSC and longitudinal TSC differences were compared between patients with initial progressive disease (PD) and patients with initial stable disease (SD) using Fisher’s exact tests and Mann-Whitney-U-tests. Univariate proportional hazard models for progression free survival (PFS) and overall survival (OS) were calculated using clinical parameters and TSC metrics as predictor variables. The analyses demonstrated that TSC developed heterogeneously over all patients following CRT. None of the TSC metrics differed significantly between cases of initial SD and initial PD. Furthermore, TSC metrics did not yield a significant association with PFS or OS. Conversely, the initial response according to the RANO criteria could significantly predict PFS [univariate HR (95%CI) = 0.02 (0.0001–0.21), p < 0.001] and OS [univariate HR = 0.17 (0.04–0.65), p = 0.005]. In conclusion, TSC showed treatment-related changes in GBM following CRT, but did not significantly correlate with the initial response according to the RANO criteria, PFS or OS. In contrast, the initial response according to the RANO criteria was a significant predictor of PFS and OS. Future investigations need to elucidate the reasons for treatment-related changes in TSC and their clinical value for response prediction in glioblastoma patients receiving CRT.
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Affiliation(s)
- Daniel Paech
- Division of Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Sebastian Regnery
- Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany.,Clinical Cooperation Unit Radiation Oncology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Tanja Platt
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Nicolas G R Behl
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany.,Siemens Healthcare GmbH, Erlangen, Germany
| | - Nina Weckesser
- Division of Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Paul Windisch
- Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany
| | | | - Wolfgang Wick
- Department of Neurology, Heidelberg University Hospital, Heidelberg, Germany
| | - Martin Bendszus
- Department of Neuroradiology, Heidelberg University Hospital, Heidelberg, Germany
| | - Stefan Rieken
- Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany.,Clinical Cooperation Unit Radiation Oncology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Laila König
- Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany.,Clinical Cooperation Unit Radiation Oncology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Mark E Ladd
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany.,Faculty of Physics and Astronomy and Faculty of Medicine, University of Heidelberg, Heidelberg, Germany
| | | | - Jürgen Debus
- Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany.,Clinical Cooperation Unit Radiation Oncology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Sebastian Adeberg
- Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany.,Clinical Cooperation Unit Radiation Oncology, German Cancer Research Center (DKFZ), Heidelberg, Germany
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32
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Platt T, Ladd ME, Paech D. 7 Tesla and Beyond: Advanced Methods and Clinical Applications in Magnetic Resonance Imaging. Invest Radiol 2021; 56:705-725. [PMID: 34510098 PMCID: PMC8505159 DOI: 10.1097/rli.0000000000000820] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 08/07/2021] [Accepted: 08/07/2021] [Indexed: 12/15/2022]
Abstract
ABSTRACT Ultrahigh magnetic fields offer significantly higher signal-to-noise ratio, and several magnetic resonance applications additionally benefit from a higher contrast-to-noise ratio, with static magnetic field strengths of B0 ≥ 7 T currently being referred to as ultrahigh fields (UHFs). The advantages of UHF can be used to resolve structures more precisely or to visualize physiological/pathophysiological effects that would be difficult or even impossible to detect at lower field strengths. However, with these advantages also come challenges, such as inhomogeneities applying standard radiofrequency excitation techniques, higher energy deposition in the human body, and enhanced B0 field inhomogeneities. The advantages but also the challenges of UHF as well as promising advanced methodological developments and clinical applications that particularly benefit from UHF are discussed in this review article.
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Affiliation(s)
- Tanja Platt
- From the Medical Physics in Radiology, German Cancer Research Center (DKFZ)
| | - Mark E. Ladd
- From the Medical Physics in Radiology, German Cancer Research Center (DKFZ)
- Faculty of Physics and Astronomy
- Faculty of Medicine, University of Heidelberg, Heidelberg
- Erwin L. Hahn Institute for MRI, University of Duisburg-Essen, Essen
| | - Daniel Paech
- Division of Radiology, German Cancer Research Center (DKFZ), Heidelberg
- Clinic for Neuroradiology, University of Bonn, Bonn, Germany
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33
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Jia F, Littin S, Amrein P, Yu H, Magill AW, Kuder TA, Bickelhaupt S, Laun F, Ladd ME, Zaitsev M. Design of a high-performance non-linear gradient coil for diffusion weighted MRI of the breast. J Magn Reson 2021; 331:107052. [PMID: 34478997 DOI: 10.1016/j.jmr.2021.107052] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 07/10/2021] [Accepted: 08/08/2021] [Indexed: 06/13/2023]
Abstract
Diffusion-weighted imaging (DWI) in the female breast is a magnetic resonance imaging (MRI) technique that complements clinical routine protocols, and that might provide an independent diagnostic value for specific clinical tasks in breast imaging. To further improve specificity of DWI in the breast, stronger and faster diffusion weighting is advantageous. Here, a dedicated gradient coil is designed, targeted at diffusion weighting in the female breast, with the peak gradient magnitude exceeding that of the current clinical MR scanners by an order of a magnitude. Design of application-tailored gradient coils in MRI has recently attracted increased attention. With the target application in mind, the gradient coil is designed on an irregularly shaped semi-open current-carrying surface. Due to the coil former closely fitting the non-spherical target region, non-linear encoding fields become particularly advantageous for achieving locally exceptionally high gradient strengths. As breast tissue has a predominantly isotropic cellular microstructure, the direction of the diffusion-weighting gradient may be allowed to vary within the target volume. However, due to the quadratic dependency of the b-factor on the gradient strength, variation of the gradient magnitude should be carefully controlled. To achieve the above design goals the corresponding multi-objective optimization problem is reformulated as a constrained optimization, allowing for flexible and precise control of the coil properties. A novel constraint is proposed, limiting gradient magnitude variation within every slice while allowing for variations in both the direction of the gradient within the slice and the magnitude across the slices. These innovations enable the design of a unilateral coil for diffusion weighting in the female breast with local gradient strengths exceeding 1 T/m with highly homogeneous diffusion weighting for imaging in the coronal slice orientation.
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Affiliation(s)
- Feng Jia
- Dept.of Radiology, Medical Physics, Medical Center University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany.
| | - Sebastian Littin
- Dept.of Radiology, Medical Physics, Medical Center University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Philipp Amrein
- Dept.of Radiology, Medical Physics, Medical Center University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Huijun Yu
- Dept.of Radiology, Medical Physics, Medical Center University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Arthur W Magill
- Division of Medical Physics in Radiology, German Cancer Researcher Center, Heidelberg, Germany
| | - Tristan A Kuder
- Division of Medical Physics in Radiology, German Cancer Researcher Center, Heidelberg, Germany
| | - Sebastian Bickelhaupt
- Junior Group Medical Imaging and Radiology-Cancer Prevention, German Cancer Research Center, Heidelberg, Germany; Institute of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Frederik Laun
- Institute of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Mark E Ladd
- Division of Medical Physics in Radiology, German Cancer Researcher Center, Heidelberg, Germany; Faculty of Physics and Astronomy and Faculty of Medicine, University of Heidelberg, Heidelberg, Germany
| | - Maxim Zaitsev
- Dept.of Radiology, Medical Physics, Medical Center University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany; High Field Magnetic Resonance Center, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
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Emmerich J, Bachert P, Ladd ME, Straub S. On the separation of susceptibility sources in quantitative susceptibility mapping: Theory and phantom validation with an in vivo application to multiple sclerosis lesions of different age. J Magn Reson 2021; 330:107033. [PMID: 34303117 DOI: 10.1016/j.jmr.2021.107033] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 06/14/2021] [Accepted: 07/08/2021] [Indexed: 06/13/2023]
Abstract
PURPOSE In biological tissue, phase contrast is determined by multiple substances such as iron, myelin or calcifications. Often, these substances occur co-located within the same measurement volume. However, quantitative susceptibility mapping can solely measure the average susceptibility per voxel. To provide new insight in disease progression and mechanisms in neurological diseases, where multiple processes such as demyelination and iron accumulation occur simultaneously in the same location, a separation of susceptibility sources is desirable to disentangle the underlying susceptibility proportions. METHODS The basic concept of separating the susceptibility effects from sources with different sign within one voxel is to include information on relaxation rate ΔR2∗ in the quantitative susceptibility mapping reconstruction pipeline. The presented reconstruction algorithm is implemented as a constrained minimization problem and solved using conjugate gradients. The algorithm is evaluated using a software phantom and validated in MRI measurements with a phantom containing mixtures of microscopic positive and negative susceptibility sources. Data from three multiple sclerosis patients are used to show in vivo feasibility. RESULTS In numerical simulations, the feasibility of disentangling susceptibility sources within the same voxel was confirmed provided the critera of the static dephasing regime were fulfilled. In phantom experiments, the magnitude decay kernel, which is an essential reconstruction parameter of the algorithm, was determined to be Dm=194.5T-1s-1ppm-1, and susceptibility sources could be separated in MRI measurement data. CONCLUSIONS In conclusion, in this study a detailed description of the implementation of an algorithm for the separation of positive and negative susceptibility sources within the same volume element as well as its limitations is presented and validated quantitatively in both simulation and phantom experiments for the first time. An application to multiple sclerosis lesions shows promising results for in vivo usability.
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Affiliation(s)
- Julian Emmerich
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany; Faculty of Physics and Astronomy, Heidelberg University, Heidelberg, Germany
| | - Peter Bachert
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany; Faculty of Physics and Astronomy, Heidelberg University, Heidelberg, Germany
| | - Mark E Ladd
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany; Faculty of Physics and Astronomy, Heidelberg University, Heidelberg, Germany; Faculty of Medicine, Heidelberg University, Heidelberg, Germany
| | - Sina Straub
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany.
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35
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Emmerich J, Bachert P, Ladd ME, Straub S. A novel phantom with dia- and paramagnetic substructure for quantitative susceptibility mapping and relaxometry. Phys Med 2021; 88:278-284. [PMID: 34332237 DOI: 10.1016/j.ejmp.2021.07.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 06/22/2021] [Accepted: 07/12/2021] [Indexed: 12/20/2022] Open
Abstract
PURPOSE A phantom is presented in this study that allows for an experimental evaluation of QSM reconstruction algorithms. The phantom contains susceptibility producing particles with dia- and paramagnetic properties embedded in an MRI visible medium and is suitable to assess the performance of algorithms that attempt to separate isotropic dia- and paramagnetic susceptibility at the sub-voxel level. METHODS The phantom was built from calcium carbonate (diamagnetic) and tungsten carbide particles (paramagnetic) embedded in gelatin and surrounded by agarose gel. Different mass fractions and mixing ratios of both susceptibility sources were used. Gradient echo data were acquired at 1.5 T, 3 T and 7 T. Susceptibility maps were calculated using the MEDI toolbox and relaxation rates ΔR2∗ were determined using exponential fitting. RESULTS Relaxation rates as well as susceptibility values generally coincide with the theoretical values for particles fulfilling the assumptions of the the static dephasing regime with stronger deviations for relaxation rates at higher field strength and for high susceptibility values. MRI raw data are available for free academic use as supplementary material. CONCLUSIONS In this study, a susceptibility phantom is presented that might find its application in the development and quantitative validation of current and future QSM reconstruction algorithms which aim to separate the influence of isotropic dia- and paramagnetic substructure in quantitative susceptibility mapping.
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Affiliation(s)
- Julian Emmerich
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany; Faculty of Physics and Astronomy, Heidelberg University, Heidelberg, Germany
| | - Peter Bachert
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany; Faculty of Physics and Astronomy, Heidelberg University, Heidelberg, Germany
| | - Mark E Ladd
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany; Faculty of Physics and Astronomy, Heidelberg University, Heidelberg, Germany; Faculty of Medicine, Heidelberg University, Heidelberg, Germany
| | - Sina Straub
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany.
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36
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Schmidt S, Bruschewski M, Flassbeck S, John K, Grundmann S, Ladd ME, Schmitter S. Phase-contrast acceleration mapping with synchronized encoding. Magn Reson Med 2021; 86:3201-3210. [PMID: 34313340 DOI: 10.1002/mrm.28948] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 06/14/2021] [Accepted: 07/15/2021] [Indexed: 11/12/2022]
Abstract
PURPOSE To develop a phase-contrast (PC) -based method for direct and unbiased quantification of the acceleration vector field by synchronization of the spatial and acceleration encoding time points. The proposed method explicitly aims at in-vitro applications, requiring high measurement accuracy, as well as the validation of clinically relevant acceleration-encoded sequences. METHODS A velocity-encoded sequence with synchronized encoding (SYNC SPI) was modified to allow direct acceleration mapping by replacing the bipolar encoding gradients with tripolar gradient waveforms. The proposed method was validated in two in-vitro flow cases: a rotation and a stenosis phantom. The thereby obtained velocity and acceleration vector fields were quantitatively compared to those acquired with conventional PC methods, as well as to theoretical data. RESULTS The rotation phantom study revealed a systematic bias of the conventional PC acceleration mapping method that resulted in an average pixel-wise relative angle between the measured and theoretical vector field of (7.8 ± 3.2)°, which was reduced to (-0.4 ± 2.7)° for the proposed SYNC SPI method. Furthermore, flow features in the stenosis phantom were displaced by up to 10 mm in the conventional PC data compared with the acceleration-encoded SYNC SPI data. CONCLUSIONS This work successfully demonstrates a highly accurate method for direct acceleration mapping. It thus complements the existing velocity-encoded SYNC SPI method to enable the direct and unbiased quantification of both the velocity and acceleration vector field for in vitro studies. Hence, this method can be used for the validation of conventional acceleration-encoded PC methods applicable in-vivo.
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Affiliation(s)
- Simon Schmidt
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany.,Faculty of Physics and Astronomy, Heidelberg University, Heidelberg, Germany.,Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, Minnesota, USA
| | | | - Sebastian Flassbeck
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany.,Department of Radiology, Center for Biomedical Imaging, New York University School of Medicine, New York, New York, USA.,Center for Advanced Imaging Innovation and Research, New York University School of Medicine, New York, New York, USA
| | - Kristine John
- Institute of Fluid Mechanics, University of Rostock, Rostock, Germany
| | - Sven Grundmann
- Institute of Fluid Mechanics, University of Rostock, Rostock, Germany
| | - Mark E Ladd
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany.,Faculty of Physics and Astronomy, Heidelberg University, Heidelberg, Germany.,Faculty of Medicine, Heidelberg University, Heidelberg, Germany
| | - Sebastian Schmitter
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany.,Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany
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Orzada S, Fiedler TM, Quick HH, Ladd ME. Post-processing algorithms for specific absorption rate compression. Magn Reson Med 2021; 86:2853-2861. [PMID: 34216047 DOI: 10.1002/mrm.28909] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 05/19/2021] [Accepted: 06/10/2021] [Indexed: 11/06/2022]
Abstract
PURPOSE Compression of local specific absorption rate (SAR) matrices is essential for enabling SAR monitoring and efficient pulse calculation in parallel transmission. Improvements in compression result in lower error margin and/or lower number of virtual observation points (VOPs). The purpose of this work is to introduce two algorithms for post-processing of already compressed VOP sets. One calculates individual overestimation matrices for the VOPs to reduce overestimation, the other identifies redundant VOPs. METHODS The first algorithm was evaluated for VOP sets calculated for three different transmit arrays with either 8 or 16 channels. For each array, two different overestimation matrices were used to generate the VOP sets. Each post-processed VOP set was evaluated using one million random excitation vectors and the results compared to the VOP set before post-processing. The second algorithm was evaluated by utilizing the same random excitation vectors and comparing the results after removal of the redundant VOPs with the results before removal to verify that these were identical. RESULTS The first algorithm reduced the mean overestimation by up to four fifths compared to the original set, while keeping the number of VOPs constant. The second algorithm decreased the number of VOPs generated by a compression with Eichfelder and Gebhardt's algorithm by more than 40% in 40% of the investigated cases and by more than 20% in 73% of the investigated cases. CONCLUSION Two post-processing algorithms are presented that enhance previously compressed VOP sets by improving the accuracy per number of VOPs.
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Affiliation(s)
- Stephan Orzada
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Thomas M Fiedler
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Harald H Quick
- Erwin L. Hahn Institute for MRI, University Duisburg-Essen, Essen, Germany.,High-Field and Hybrid MR Imaging, University Hospital Essen, Essen, Germany
| | - Mark E Ladd
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany.,Erwin L. Hahn Institute for MRI, University Duisburg-Essen, Essen, Germany.,Faculty of Physics and Astronomy, University of Heidelberg, Heidelberg, Germany.,Faculty of Medicine, University of Heidelberg, Heidelberg, Germany
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38
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Fiedler TM, Orzada S, Flöser M, Rietsch SHG, Quick HH, Ladd ME, Bitz AK. Performance analysis of integrated RF microstrip transmit antenna arrays with high channel count for body imaging at 7 T. NMR Biomed 2021; 34:e4515. [PMID: 33942938 DOI: 10.1002/nbm.4515] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Revised: 02/18/2021] [Accepted: 03/09/2021] [Indexed: 05/12/2023]
Abstract
The aim of the current study was to investigate the performance of integrated RF transmit arrays with high channel count consisting of meander microstrip antennas for body imaging at 7 T and to optimize the position and number of transmit elements. RF simulations using multiring antenna arrays placed behind the bore liner were performed for realistic exposure conditions for body imaging. Simulations were performed for arrays with as few as eight elements and for arrays with high channel counts of up to 48 elements. The B1+ field was evaluated regarding the degrees of freedom for RF shimming in the abdomen. Worst-case specific absorption rate (SARwc ), SAR overestimation in the matrix compression, the number of virtual observation points (VOPs) and SAR efficiency were evaluated. Constrained RF shimming was performed in differently oriented regions of interest in the body, and the deviation from a target B1+ field was evaluated. Results show that integrated multiring arrays are able to generate homogeneous B1+ field distributions for large FOVs, especially for coronal/sagittal slices, and thus enable body imaging at 7 T with a clinical workflow; however, a low duty cycle or a high SAR is required to achieve homogeneous B1+ distributions and to exploit the full potential. In conclusion, integrated arrays allow for high element counts that have high degrees of freedom for the pulse optimization but also produce high SARwc , which reduces the SAR accuracy in the VOP compression for low-SAR protocols, leading to a potential reduction in array performance. Smaller SAR overestimations can increase SAR accuracy, but lead to a high number of VOPs, which increases the computational cost for VOP evaluation and makes online SAR monitoring or pulse optimization challenging. Arrays with interleaved rings showed the best results in the study.
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Affiliation(s)
- Thomas M Fiedler
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Stephan Orzada
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Erwin L. Hahn Institute for MRI, University Duisburg-Essen, Essen, Germany
- High-Field and Hybrid MR Imaging, University Hospital Essen, Essen, Germany
| | - Martina Flöser
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Stefan H G Rietsch
- Erwin L. Hahn Institute for MRI, University Duisburg-Essen, Essen, Germany
- High-Field and Hybrid MR Imaging, University Hospital Essen, Essen, Germany
| | - Harald H Quick
- Erwin L. Hahn Institute for MRI, University Duisburg-Essen, Essen, Germany
- High-Field and Hybrid MR Imaging, University Hospital Essen, Essen, Germany
| | - Mark E Ladd
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Erwin L. Hahn Institute for MRI, University Duisburg-Essen, Essen, Germany
- Faculty of Physics and Astronomy, University of Heidelberg, Heidelberg, Germany
- Faculty of Medicine, University of Heidelberg, Heidelberg, Germany
| | - Andreas K Bitz
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Electromagnetic Theory and Applied Mathematics, Faculty of Electrical Engineering and Information Technology, FH Aachen - University of Applied Sciences, Aachen, Germany
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Schneider TM, Ma J, Wagner P, Behl N, Nagel AM, Ladd ME, Heiland S, Bendszus M, Straub S. Multiparametric MRI for Characterization of the Basal Ganglia and the Midbrain. Front Neurosci 2021; 15:661504. [PMID: 34234639 PMCID: PMC8255625 DOI: 10.3389/fnins.2021.661504] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Accepted: 05/17/2021] [Indexed: 12/02/2022] Open
Abstract
Objectives To characterize subcortical nuclei by multi-parametric quantitative magnetic resonance imaging. Materials and Methods: The following quantitative multiparametric MR data of five healthy volunteers were acquired on a 7T MRI system: 3D gradient echo (GRE) data for the calculation of quantitative susceptibility maps (QSM), GRE sequences with and without off-resonant magnetic transfer pulse for magnetization transfer ratio (MTR) calculation, a magnetization−prepared 2 rapid acquisition gradient echo sequence for T1 mapping, and (after a coil change) a density-adapted 3D radial pulse sequence for 23Na imaging. First, all data were co-registered to the GRE data, volumes of interest (VOIs) for 21 subcortical structures were drawn manually for each volunteer, and a combined voxel-wise analysis of the four MR contrasts (QSM, MTR, T1, 23Na) in each structure was conducted to assess the quantitative, MR value-based differentiability of structures. Second, a machine learning algorithm based on random forests was trained to automatically classify the groups of multi-parametric voxel values from each VOI according to their association to one of the 21 subcortical structures. Results The analysis of the integrated multimodal visualization of quantitative MR values in each structure yielded a successful classification among nuclei of the ascending reticular activation system (ARAS), the limbic system and the extrapyramidal system, while classification among (epi-)thalamic nuclei was less successful. The machine learning-based approach facilitated quantitative MR value-based structure classification especially in the group of extrapyramidal nuclei and reached an overall accuracy of 85% regarding all selected nuclei. Conclusion Multimodal quantitative MR enabled excellent differentiation of a wide spectrum of subcortical nuclei with reasonable accuracy and may thus enable sensitive detection of disease and nucleus-specific MR-based contrast alterations in the future.
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Affiliation(s)
- Till M Schneider
- Department of Neuroradiology, University of Heidelberg, Heidelberg, Germany
| | - Jackie Ma
- Department of Artificial Intelligence, Fraunhofer Heinrich Hertz Institute, Berlin, Germany
| | - Patrick Wagner
- Department of Artificial Intelligence, Fraunhofer Heinrich Hertz Institute, Berlin, Germany
| | - Nicolas Behl
- Division of Medical Physics in Radiology, German Cancer Research Center, Heidelberg, Germany
| | - Armin M Nagel
- Division of Medical Physics in Radiology, German Cancer Research Center, Heidelberg, Germany.,Institute of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Mark E Ladd
- Division of Medical Physics in Radiology, German Cancer Research Center, Heidelberg, Germany.,Faculty of Physics and Astronomy and Faculty of Medicine, University of Heidelberg, Heidelberg, Germany
| | - Sabine Heiland
- Department of Neuroradiology, University of Heidelberg, Heidelberg, Germany
| | - Martin Bendszus
- Department of Neuroradiology, University of Heidelberg, Heidelberg, Germany
| | - Sina Straub
- Division of Medical Physics in Radiology, German Cancer Research Center, Heidelberg, Germany
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40
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Kratzer FJ, Flassbeck S, Schmitter S, Wilferth T, Magill AW, Knowles BR, Platt T, Bachert P, Ladd ME, Nagel AM. 3D sodium ( 23 Na) magnetic resonance fingerprinting for time-efficient relaxometric mapping. Magn Reson Med 2021; 86:2412-2425. [PMID: 34061397 DOI: 10.1002/mrm.28873] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 04/16/2021] [Accepted: 05/08/2021] [Indexed: 11/07/2022]
Abstract
PURPOSE To develop a framework for 3D sodium (23 Na) MR fingerprinting (MRF), based on irreducible spherical tensor operators with tailored flip angle (FA) pattern and time-efficient data acquisition for simultaneous quantification of T1 , T 2 l ∗ , T 2 s ∗ , and T 2 ∗ in addition to ΔB0 . METHODS 23 Na-MRF was implemented in a 3D sequence and irreducible spherical tensor operators were exploited in the simulations. Furthermore, the Cramér Rao lower bound was used to optimize the flip angle pattern. A combination of single and double echo readouts was implemented to increase the readout efficiency. A study was conducted to compare results in a multicompartment phantom acquired with MRF and reference methods. Finally, the relaxation times in the human brain were measured in four healthy volunteers. RESULTS Phantom experiments revealed a mean difference of 1.0% between relaxation times acquired with MRF and results determined with the reference methods. Simultaneous quantification of the longitudinal and transverse relaxation times in the human brain was possible within 32 min using 3D 23 Na-MRF with a nominal resolution of (5 mm)3 . In vivo measurements in four volunteers yielded average relaxation times of: T1,brain = (35.0 ± 3.2) ms, T 2 l , brain ∗ = (29.3 ± 3.8) ms and T 2 s , brain ∗ = (5.5 ± 1.3) ms in brain tissue, whereas T1,CSF = (61.9 ± 2.8) ms and T 2 , CSF ∗ = (46.3 ± 4.5) ms was found in cerebrospinal fluid. CONCLUSION The feasibility of in vivo 3D relaxometric sodium mapping within roughly ½ h is demonstrated using MRF in the human brain, moving sodium relaxometric mapping toward clinically relevant measurement times.
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Affiliation(s)
- Fabian J Kratzer
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Faculty of Physics and Astronomy, Ruprecht-Karls University Heidelberg, Heidelberg, Germany
| | - Sebastian Flassbeck
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Center for Biomedical Imaging, Department of Radiology, New York University, New York, New York, USA
- Center for Advanced Imaging Innovation and Research, New York University, New York, New York, USA
| | - Sebastian Schmitter
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Berlin, Germany
| | - Tobias Wilferth
- Institute of Radiology, Friedrich-Alexander University Erlangen-Nürnberg (FAU), University Hospital Erlangen, Erlangen, Germany
| | - Arthur W Magill
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Benjamin R Knowles
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Tanja Platt
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Peter Bachert
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Faculty of Physics and Astronomy, Ruprecht-Karls University Heidelberg, Heidelberg, Germany
| | - Mark E Ladd
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Faculty of Physics and Astronomy, Ruprecht-Karls University Heidelberg, Heidelberg, Germany
- Faculty of Medicine, Ruprecht-Karls University Heidelberg, Heidelberg, Germany
| | - Armin M Nagel
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Institute of Radiology, Friedrich-Alexander University Erlangen-Nürnberg (FAU), University Hospital Erlangen, Erlangen, Germany
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Voelker MN, Kraff O, Goerke S, Laun FB, Hanspach J, Pine KJ, Ehses P, Zaiss M, Liebert A, Straub S, Eckstein K, Robinson S, Nagel AN, Stefanescu MR, Wollrab A, Klix S, Felder J, Hock M, Bosch D, Weiskopf N, Speck O, Ladd ME, Quick HH. The traveling heads 2.0: Multicenter reproducibility of quantitative imaging methods at 7 Tesla. Neuroimage 2021; 232:117910. [PMID: 33647497 DOI: 10.1016/j.neuroimage.2021.117910] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 01/25/2021] [Accepted: 02/20/2021] [Indexed: 12/14/2022] Open
Abstract
OBJECT This study evaluates inter-site and intra-site reproducibility at ten different 7 T sites for quantitative brain imaging. MATERIAL AND METHODS Two subjects - termed the "traveling heads" - were imaged at ten different 7 T sites with a harmonized quantitative brain MR imaging protocol. In conjunction with the system calibration, MP2RAGE, QSM, CEST and multi-parametric mapping/relaxometry were examined. RESULTS Quantitative measurements with MP2RAGE showed very high reproducibility across sites and subjects, and errors were in concordance with previous results and other field strengths. QSM had high inter-site reproducibility for relevant subcortical volumes. CEST imaging revealed systematic differences between the sites, but reproducibility was comparable to results in the literature. Relaxometry had also very high agreement between sites, but due to the high sensitivity, differences caused by different applications of the B1 calibration of the two RF coil types used were observed. CONCLUSION Our results show that quantitative brain imaging can be performed with high reproducibility at 7 T and with similar reliability as found at 3 T for multicenter studies of the supratentorial brain.
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Affiliation(s)
- Maximilian N Voelker
- Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany; High-Field and Hybrid MR Imaging, University Hospital Essen, University Duisburg-Essen, Essen, Germany.
| | - Oliver Kraff
- Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany
| | - Steffen Goerke
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Frederik B Laun
- Institute of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Jannis Hanspach
- Institute of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Kerrin J Pine
- Department of Neurophysics, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - Philipp Ehses
- German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Moritz Zaiss
- Institute of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany; Max Planck Institute for Biological Cybernetics, Tübingen, Germany
| | - Andrzej Liebert
- Institute of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Sina Straub
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Korbinian Eckstein
- High Field MR Center, Department for Biomedical Imaging and Image guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Simon Robinson
- High Field MR Center, Department for Biomedical Imaging and Image guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Armin N Nagel
- Institute of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Maria R Stefanescu
- Chair of Cellular and Molecular Imaging, Comprehensive Heart Failure Center (CHFC), University Hospital Wuerzburg, Wuerzburg, Germany
| | - Astrid Wollrab
- Otto-von-Guericke-University Magdeburg, Magdeburg, Germany
| | - Sabrina Klix
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrueck-Center for Molecular Medicine, Berlin-Buch, Germany
| | - Jörg Felder
- Institute of Neuroscience and Medicine (INM-4), Forschungszentrum Jülich, Jülich, Germany
| | - Michael Hock
- Chair of Cellular and Molecular Imaging, Comprehensive Heart Failure Center (CHFC), University Hospital Wuerzburg, Wuerzburg, Germany
| | - Dario Bosch
- Max Planck Institute for Biological Cybernetics, Tübingen, Germany
| | - Nikolaus Weiskopf
- Department of Neurophysics, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany; Felix Bloch Institute for Solid State Physics, Faculty of Physics and Earth Sciences, Leipzig University, Leipzig, Germany
| | - Oliver Speck
- Otto-von-Guericke-University Magdeburg, Magdeburg, Germany; Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Mark E Ladd
- Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany; Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany; Faculty of Medicine and Faculty of Physics and Astronomy, Heidelberg University, Heidelberg, Germany
| | - Harald H Quick
- Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany; High-Field and Hybrid MR Imaging, University Hospital Essen, University Duisburg-Essen, Essen, Germany
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Orzada S, Fiedler TM, Quick HH, Ladd ME. Local SAR compression algorithm with improved compression, speed, and flexibility. Magn Reson Med 2021; 86:561-568. [PMID: 33634530 DOI: 10.1002/mrm.28739] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 01/12/2021] [Accepted: 01/28/2021] [Indexed: 01/07/2023]
Abstract
PURPOSE Local specific absorption rate (SAR) compression algorithms are essential for enabling online SAR monitoring in parallel transmission. A better compression resulting in a lower number of virtual observation points improves speed of SAR calculation for online supervision and pulse design. METHOD An iterative expansion of an existing algorithm presented by Lee et al is proposed in this work. The original algorithm is used within a loop, making use of the virtual observation points from the previous iteration as the starting subvolume, while decreasing the overestimation with each iteration. This algorithm is evaluated on the SAR matrices of three different simulated arrays. RESULT The number of virtual observation points is approximately halved with the new algorithm, while at the same time the compression time is reduced with speed-up factors of up to 2.5. CONCLUSION The new algorithm improves the original algorithm in terms of compression rate and speed.
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Affiliation(s)
- Stephan Orzada
- Medical Physics in Radiology, German Cancer Research Center, Heidelberg, Germany
| | - Thomas M Fiedler
- Medical Physics in Radiology, German Cancer Research Center, Heidelberg, Germany
| | - Harald H Quick
- Erwin L. Hahn Institute for MRI, University Duisburg-Essen, Essen, Germany.,High-Field and Hybrid MR Imaging, University Hospital Essen, Essen, Germany
| | - Mark E Ladd
- Medical Physics in Radiology, German Cancer Research Center, Heidelberg, Germany.,Erwin L. Hahn Institute for MRI, University Duisburg-Essen, Essen, Germany.,Faculty of Physics and Astronomy, University of Heidelberg, Heidelberg, Germany.,Faculty of Medicine, University of Heidelberg, Heidelberg, Germany
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43
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Goerke S, Breitling J, Korzowski A, Paech D, Zaiss M, Schlemmer HP, Ladd ME, Bachert P. Clinical routine acquisition protocol for 3D relaxation-compensated APT and rNOE CEST-MRI of the human brain at 3T. Magn Reson Med 2021; 86:393-404. [PMID: 33586217 DOI: 10.1002/mrm.28699] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 12/10/2020] [Accepted: 01/05/2021] [Indexed: 12/14/2022]
Abstract
PURPOSE The value of relaxation-compensated amide proton transfer (APT) and relayed nuclear Overhauser effect (rNOE) chemical exchange saturation transfer (CEST)-MRI has already been demonstrated in various neuro-oncological clinical applications. Recently, we translated the approach from 7T to a clinically relevant magnetic field strength of 3T. However, the overall acquisition time was still too long for a broad application in the clinical setting. The aim of this study was to establish a shorter acquisition protocol whilst maintaining the contrast behavior and reproducibility. METHODS Ten patients with glioblastoma were examined using the previous state-of-the-art acquisition protocol at 3T. The acquired spectral data were retrospectively reduced to find the minimal amount of required information that allows obtaining the same contrast behavior. To further reduce the acquisition time, also the image readout was accelerated and the pre-saturation parameters were further optimized. RESULTS In total, the overall acquisition time could be reduced from 19 min to under 7 min. One key finding was that, when evaluated by the relaxation-compensated inverse metric, a contrast correction for B1 -field inhomogeneities at 3T can also be achieved reliably with CEST data at only one B1 value. In contrast, a 1-point B1 -correction was not sufficient for the common linear difference evaluation. The reproducibility of the new clinical routine acquisition protocol was similar to the previous state-of-the-art protocol with limits of agreement below 20%. CONCLUSIONS The substantial reduction in acquisition time by about 64% now allows the application of 3D relaxation-compensated APT and rNOE CEST-MRI for examinations of the human brain at 3T in clinical routine.
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Affiliation(s)
- Steffen Goerke
- Department of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Johannes Breitling
- Department of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Andreas Korzowski
- Department of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Daniel Paech
- Department of Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Moritz Zaiss
- Department of Neuroradiology, University Hospital Erlangen, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Erlangen, Germany.,High-field Magnetic Resonance Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany
| | - Heinz-Peter Schlemmer
- Department of Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany.,Faculty of Medicine, University of Heidelberg, Heidelberg, Germany
| | - Mark E Ladd
- Department of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany.,Faculty of Medicine, University of Heidelberg, Heidelberg, Germany.,Faculty of Physics and Astronomy, University of Heidelberg, Heidelberg, Germany
| | - Peter Bachert
- Department of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany.,Faculty of Physics and Astronomy, University of Heidelberg, Heidelberg, Germany
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Schmidt S, Flassbeck S, Schmelter S, Schmeyer E, Ladd ME, Schmitter S. The impact of 4D flow displacement artifacts on wall shear stress estimation. Magn Reson Med 2021; 85:3154-3168. [PMID: 33421221 DOI: 10.1002/mrm.28641] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 11/16/2020] [Accepted: 11/23/2020] [Indexed: 12/27/2022]
Abstract
PURPOSE To investigate the amplitude and spatial distribution of errors in wall shear stress (WSS) values derived from 4D flow measurements caused by displacement artifacts intrinsic to the 4D flow acquisition. METHODS Phase-contrast MRI velocimetry was performed in a model of a stenotic aorta using two different timing schemes, both of which are commonly applied in vivo but differ in their resulting displacement artifacts. Whereas one scheme is optimized to minimize the duration of the encoding gradients (herein called FAST), the other aims to specifically minimize displacement artifacts by synchronizing all three spatial-encoding time points (called ECHO). WSS estimates were calculated and compared to unbiased WSS values obtained by a 5-hour single-point imaging acquisition. In addition, MRI simulations based on computational fluid dynamics data were carried out to investigate the impact of gradient timings corresponding to different spatial resolutions. RESULTS 4D flow displacement artifacts were found to have an impact on the quantified WSS peak values, spatial location, and overall WSS pattern. FAST leads to the underestimation of local WSS values in the phantom arch by up to 90%. Moreover, the corresponding WSS estimates depend on the image orientation. This effect was avoided using ECHO, which, however, results in biased WSS values within the stenosis, yielding an underestimation of peak WSS by up to 17%. Computational fluid dynamics-based simulation results show that the bias in WSS due to displacement artifacts increases with increasing spatial resolution, thus counteracting the resolution benefit for WSS due to reduced partial volume effects and segmentation errors. CONCLUSIONS 4D flow displacement artifacts can significantly impact the WSS estimates and depend on the timing scheme as well as potentially the image orientation. Whereas FAST might allow correct WSS estimation for lower resolutions, ECHO is recommended especially when spatial resolutions of 1 mm and smaller are used. Users need to be aware of this nonnegligible effect, particularly when conducting inter-site studies or studies between vendors. The timing scheme should thus be explicitly mentioned in publications.
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Affiliation(s)
- Simon Schmidt
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany.,Faculty of Physics and Astronomy, Heidelberg University, Heidelberg, Germany
| | - Sebastian Flassbeck
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany.,Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, NY, USA.,Center for Advanced Imaging Innovation and Research, New York University School of Medicine, New York, NY, USA
| | - Sonja Schmelter
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany
| | - Ellen Schmeyer
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany
| | - Mark E Ladd
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany.,Faculty of Physics and Astronomy, Heidelberg University, Heidelberg, Germany.,Faculty of Medicine, Heidelberg University, Heidelberg, Germany
| | - Sebastian Schmitter
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany.,Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany
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Friedrich F, Hörner-Rieber J, Renkamp CK, Klüter S, Bachert P, Ladd ME, Knowles BR. Stability of conventional and machine learning-based tumor auto-segmentation techniques using undersampled dynamic radial bSSFP acquisitions on a 0.35 T hybrid MR-linac system. Med Phys 2021; 48:587-596. [PMID: 33319394 DOI: 10.1002/mp.14659] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 12/08/2020] [Accepted: 12/08/2020] [Indexed: 11/11/2022] Open
Abstract
PURPOSE Hybrid MRI-linear accelerator systems (MR-linacs) allow for the incorporation of MR images with high soft-tissue contrast into the radiation therapy procedure prior to, during, or post irradiation. This allows not only for the optimization of the treatment planning, but also for real-time monitoring of the tumor position using cine MRI, from which intrafractional motion can be compensated. Fast imaging and accurate tumor tracking are crucial for effective compensation. This study investigates the application of cine MRI with a radial acquisition scheme on a low-field MR-linac to accelerate the acquisition rate and evaluates the effect on tracking accuracy. METHODS An MR sequence using tiny golden-angle radial k-space sampling was developed and applied to cine imaging on patients with liver tumors on a 0.35 T MR-linac. Tumor tracking was assessed for accuracy and stability from the cine images with increasing k-space undersampling factors. Tracking was achieved using two different auto-segmentation algorithms: a deformable image registration B-spline similar to that implemented on the MR-linac and a convolutional neural network approach known as U-Net. RESULTS Radial imaging allows for increased temporal resolution with reliable tumor tracking, although tracking robustness decreases as temporal resolution increases. Additional acquisition-based artifacts can be avoided by reducing the angle increment using tiny golden-angles. The U-net algorithm was found to have superior auto-segmentation metrics compared to B-spline. U-net was able to track two well-defined tumors, imaged with just 30 spokes per image (10.6 frames per second), with an average Dice coefficient ≥ 83%, Hausdorff distance ≤ 1.4 pixel, and mean contour distance ≤ 0.5 pixel. CONCLUSIONS Radial acquisitions are commonplace in dynamic imaging; however, in MR-guided radiotherapy, robust tumor tracking is also required. This study demonstrates the in vivo feasibility of tumor tracking from radially acquired images on a low-field MR-linac. Radial imaging allows for decreased image acquisition times while maintaining robust tracking. The U-net algorithm can track a tumor with higher accuracy in images with undersampling artifacts than a conventional deformable B-spline algorithm and is a promising tool for tracking in MR-guided radiation therapy.
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Affiliation(s)
- Florian Friedrich
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, Heidelberg, 69120, Germany.,Faculty of Physics and Astronomy, University of Heidelberg, Im Neuenheimer Feld 226, Heidelberg, 69120, Germany
| | - Juliane Hörner-Rieber
- Department of Radiation Oncology, University Hospital of Heidelberg, Im Neuenheimer Feld 400, Heidelberg, 69120, Germany.,Heidelberg Institute of Radiation Oncology (HIRO), Im Neuenheimer Feld 400, Heidelberg, 69120, Germany.,National Center for Radiation Research in Oncology (NCRO), Im Neuenheimer Feld 400, Heidelberg, 69120, Germany.,Clinical Cooperation Unit Radiation Oncology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, Heidelberg, 69120, Germany
| | - C Katharina Renkamp
- Department of Radiation Oncology, University Hospital of Heidelberg, Im Neuenheimer Feld 400, Heidelberg, 69120, Germany.,Heidelberg Institute of Radiation Oncology (HIRO), Im Neuenheimer Feld 400, Heidelberg, 69120, Germany.,National Center for Radiation Research in Oncology (NCRO), Im Neuenheimer Feld 400, Heidelberg, 69120, Germany
| | - Sebastian Klüter
- Department of Radiation Oncology, University Hospital of Heidelberg, Im Neuenheimer Feld 400, Heidelberg, 69120, Germany.,Heidelberg Institute of Radiation Oncology (HIRO), Im Neuenheimer Feld 400, Heidelberg, 69120, Germany.,National Center for Radiation Research in Oncology (NCRO), Im Neuenheimer Feld 400, Heidelberg, 69120, Germany
| | - Peter Bachert
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, Heidelberg, 69120, Germany.,Faculty of Physics and Astronomy, University of Heidelberg, Im Neuenheimer Feld 226, Heidelberg, 69120, Germany
| | - Mark E Ladd
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, Heidelberg, 69120, Germany.,Faculty of Physics and Astronomy, University of Heidelberg, Im Neuenheimer Feld 226, Heidelberg, 69120, Germany.,Faculty of Medicine, University of Heidelberg, Im Neuenheimer Feld 672, Heidelberg, 69120, Germany
| | - Benjamin R Knowles
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, Heidelberg, 69120, Germany
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Otazo R, Lambin P, Pignol JP, Ladd ME, Schlemmer HP, Baumann M, Hricak H. MRI-guided Radiation Therapy: An Emerging Paradigm in Adaptive Radiation Oncology. Radiology 2020; 298:248-260. [PMID: 33350894 DOI: 10.1148/radiol.2020202747] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Radiation therapy (RT) continues to be one of the mainstays of cancer treatment. Considerable efforts have been recently devoted to integrating MRI into clinical RT planning and monitoring. This integration, known as MRI-guided RT, has been motivated by the superior soft-tissue contrast, organ motion visualization, and ability to monitor tumor and tissue physiologic changes provided by MRI compared with CT. Offline MRI is already used for treatment planning at many institutions. Furthermore, MRI-guided linear accelerator systems, allowing use of MRI during treatment, enable improved adaptation to anatomic changes between RT fractions compared with CT guidance. Efforts are underway to develop real-time MRI-guided intrafraction adaptive RT of tumors affected by motion and MRI-derived biomarkers to monitor treatment response and potentially adapt treatment to physiologic changes. These developments in MRI guidance provide the basis for a paradigm change in treatment planning, monitoring, and adaptation. Key challenges to advancing MRI-guided RT include real-time volumetric anatomic imaging, addressing image distortion because of magnetic field inhomogeneities, reproducible quantitative imaging across different MRI systems, and biologic validation of quantitative imaging. This review describes emerging innovations in offline and online MRI-guided RT, exciting opportunities they offer for advancing research and clinical care, hurdles to be overcome, and the need for multidisciplinary collaboration.
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Affiliation(s)
- Ricardo Otazo
- From the Departments of Medical Physics (R.O.) and Radiology (R.O., H.H.), Memorial Sloan-Kettering Cancer Center, 1275 York Ave, New York, NY 10065; The D-Lab, Department of Precision Medicine, Department of Radiology & Nuclear Medicine, GROW-School for Oncology, Maastricht University Medical Centre, Maastricht, the Netherlands (P.L.); Department of Radiation Oncology, Dalhousie University, Halifax, Canada (J.P.P.); Divisions of Medical Physics in Radiology (M.E.L.), Radiology (H.P.S.), and Radiation Oncology/Radiobiology (M.B.), German Cancer Research Center (DKFZ), Heidelberg, Germany; Faculty of Physics and Astronomy (M.E.L.) and Faculty of Medicine (M.E.L., M.B.), Heidelberg University, Heidelberg, Germany; and OncoRay-National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany (M.B.)
| | - Philippe Lambin
- From the Departments of Medical Physics (R.O.) and Radiology (R.O., H.H.), Memorial Sloan-Kettering Cancer Center, 1275 York Ave, New York, NY 10065; The D-Lab, Department of Precision Medicine, Department of Radiology & Nuclear Medicine, GROW-School for Oncology, Maastricht University Medical Centre, Maastricht, the Netherlands (P.L.); Department of Radiation Oncology, Dalhousie University, Halifax, Canada (J.P.P.); Divisions of Medical Physics in Radiology (M.E.L.), Radiology (H.P.S.), and Radiation Oncology/Radiobiology (M.B.), German Cancer Research Center (DKFZ), Heidelberg, Germany; Faculty of Physics and Astronomy (M.E.L.) and Faculty of Medicine (M.E.L., M.B.), Heidelberg University, Heidelberg, Germany; and OncoRay-National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany (M.B.)
| | - Jean-Philippe Pignol
- From the Departments of Medical Physics (R.O.) and Radiology (R.O., H.H.), Memorial Sloan-Kettering Cancer Center, 1275 York Ave, New York, NY 10065; The D-Lab, Department of Precision Medicine, Department of Radiology & Nuclear Medicine, GROW-School for Oncology, Maastricht University Medical Centre, Maastricht, the Netherlands (P.L.); Department of Radiation Oncology, Dalhousie University, Halifax, Canada (J.P.P.); Divisions of Medical Physics in Radiology (M.E.L.), Radiology (H.P.S.), and Radiation Oncology/Radiobiology (M.B.), German Cancer Research Center (DKFZ), Heidelberg, Germany; Faculty of Physics and Astronomy (M.E.L.) and Faculty of Medicine (M.E.L., M.B.), Heidelberg University, Heidelberg, Germany; and OncoRay-National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany (M.B.)
| | - Mark E Ladd
- From the Departments of Medical Physics (R.O.) and Radiology (R.O., H.H.), Memorial Sloan-Kettering Cancer Center, 1275 York Ave, New York, NY 10065; The D-Lab, Department of Precision Medicine, Department of Radiology & Nuclear Medicine, GROW-School for Oncology, Maastricht University Medical Centre, Maastricht, the Netherlands (P.L.); Department of Radiation Oncology, Dalhousie University, Halifax, Canada (J.P.P.); Divisions of Medical Physics in Radiology (M.E.L.), Radiology (H.P.S.), and Radiation Oncology/Radiobiology (M.B.), German Cancer Research Center (DKFZ), Heidelberg, Germany; Faculty of Physics and Astronomy (M.E.L.) and Faculty of Medicine (M.E.L., M.B.), Heidelberg University, Heidelberg, Germany; and OncoRay-National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany (M.B.)
| | - Heinz-Peter Schlemmer
- From the Departments of Medical Physics (R.O.) and Radiology (R.O., H.H.), Memorial Sloan-Kettering Cancer Center, 1275 York Ave, New York, NY 10065; The D-Lab, Department of Precision Medicine, Department of Radiology & Nuclear Medicine, GROW-School for Oncology, Maastricht University Medical Centre, Maastricht, the Netherlands (P.L.); Department of Radiation Oncology, Dalhousie University, Halifax, Canada (J.P.P.); Divisions of Medical Physics in Radiology (M.E.L.), Radiology (H.P.S.), and Radiation Oncology/Radiobiology (M.B.), German Cancer Research Center (DKFZ), Heidelberg, Germany; Faculty of Physics and Astronomy (M.E.L.) and Faculty of Medicine (M.E.L., M.B.), Heidelberg University, Heidelberg, Germany; and OncoRay-National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany (M.B.)
| | - Michael Baumann
- From the Departments of Medical Physics (R.O.) and Radiology (R.O., H.H.), Memorial Sloan-Kettering Cancer Center, 1275 York Ave, New York, NY 10065; The D-Lab, Department of Precision Medicine, Department of Radiology & Nuclear Medicine, GROW-School for Oncology, Maastricht University Medical Centre, Maastricht, the Netherlands (P.L.); Department of Radiation Oncology, Dalhousie University, Halifax, Canada (J.P.P.); Divisions of Medical Physics in Radiology (M.E.L.), Radiology (H.P.S.), and Radiation Oncology/Radiobiology (M.B.), German Cancer Research Center (DKFZ), Heidelberg, Germany; Faculty of Physics and Astronomy (M.E.L.) and Faculty of Medicine (M.E.L., M.B.), Heidelberg University, Heidelberg, Germany; and OncoRay-National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany (M.B.)
| | - Hedvig Hricak
- From the Departments of Medical Physics (R.O.) and Radiology (R.O., H.H.), Memorial Sloan-Kettering Cancer Center, 1275 York Ave, New York, NY 10065; The D-Lab, Department of Precision Medicine, Department of Radiology & Nuclear Medicine, GROW-School for Oncology, Maastricht University Medical Centre, Maastricht, the Netherlands (P.L.); Department of Radiation Oncology, Dalhousie University, Halifax, Canada (J.P.P.); Divisions of Medical Physics in Radiology (M.E.L.), Radiology (H.P.S.), and Radiation Oncology/Radiobiology (M.B.), German Cancer Research Center (DKFZ), Heidelberg, Germany; Faculty of Physics and Astronomy (M.E.L.) and Faculty of Medicine (M.E.L., M.B.), Heidelberg University, Heidelberg, Germany; and OncoRay-National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany (M.B.)
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Orzada S, Fiedler TM, Bitz AK, Ladd ME, Quick HH. Local SAR compression with overestimation control to reduce maximum relative SAR overestimation and improve multi-channel RF array performance. MAGMA 2020; 34:153-163. [PMID: 32964299 PMCID: PMC7910258 DOI: 10.1007/s10334-020-00890-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 08/31/2020] [Accepted: 09/11/2020] [Indexed: 11/18/2022]
Abstract
Objective In local SAR compression algorithms, the overestimation is generally not linearly dependent on actual local SAR. This can lead to large relative overestimation at low actual SAR values, unnecessarily constraining transmit array performance. Method Two strategies are proposed to reduce maximum relative overestimation for a given number of VOPs. The first strategy uses an overestimation matrix that roughly approximates actual local SAR; the second strategy uses a small set of pre-calculated VOPs as the overestimation term for the compression. Result Comparison with a previous method shows that for a given maximum relative overestimation the number of VOPs can be reduced by around 20% at the cost of a higher absolute overestimation at high actual local SAR values. Conclusion The proposed strategies outperform a previously published strategy and can improve the SAR compression where maximum relative overestimation constrains the performance of parallel transmission.
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Affiliation(s)
- Stephan Orzada
- Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Kokereiallee 7, 45141, Essen, Germany. .,High-Field and Hybrid MR Imaging, University Hospital Essen, 45147, Essen, Germany.
| | - Thomas M Fiedler
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120, Heidelberg, Germany
| | - Andreas K Bitz
- Electromagnetic Theory and Applied Mathematics, Faculty of Electrical Engineering and Information Technology, FH Aachen, University of Applied Sciences, 52066, Aachen, Germany
| | - Mark E Ladd
- Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Kokereiallee 7, 45141, Essen, Germany.,Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120, Heidelberg, Germany.,Faculty of Physics and Astronomy, University of Heidelberg, Im Neuenheimer Feld 226, 69120, Heidelberg, Germany.,Faculty of Medicine, University of Heidelberg, Im Neuenheimer Feld 672, 69120, Heidelberg, Germany
| | - Harald H Quick
- Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Kokereiallee 7, 45141, Essen, Germany.,High-Field and Hybrid MR Imaging, University Hospital Essen, 45147, Essen, Germany
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48
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Regnery S, Behl NGR, Platt T, Weinfurtner N, Windisch P, Deike-Hofmann K, Sahm F, Bendszus M, Debus J, Ladd ME, Schlemmer HP, Rieken S, Adeberg S, Paech D. Ultra-high-field sodium MRI as biomarker for tumor extent, grade and IDH mutation status in glioma patients. Neuroimage Clin 2020; 28:102427. [PMID: 33002860 PMCID: PMC7527584 DOI: 10.1016/j.nicl.2020.102427] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 04/21/2020] [Accepted: 09/08/2020] [Indexed: 12/24/2022]
Abstract
PURPOSE This prospective clinical trial investigated sodium (23Na) MRI at 7 Tesla (T) field strength as biomarker for tumor extent, isocitrate dehydrogenase (IDH) mutation and O6-methylguanine DNA methyltransferase (MGMT) promotor methylation in glioma patients. METHODS 28 glioma patients underwent 23Na MRI on a 7T scanner (Siemens Healthcare, Erlangen, Germany) parallel to standard 3T MRI before chemoradiation. Areas of Gadolinium-contrast enhancement (gdce), non-enhancing T2-hyperintensity (regarded as edema), necrosis, and normal-appearing white matter (nawm) were segmented on 3T MRI imaging and were co-registered with the 23Na images. The median total 23Na concentrations of all areas were compared by pairwise t-tests. Furthermore, areas of gdce and edema were merged to yield the whole tumor area without necrosis. Subsequently, the difference in median of the 23Na concentration of this whole tumor area was compared between IDH-mutated and IDH wild-type gliomas as well as MGMT methylated and MGMT not-methylated glioblastomas using Whitney-Mann U-tests. All p-values were corrected after the Bonferroni-Holm procedure. RESULTS The 23Na concentration increased successively from nawm to necrotic areas (mean ± sd: nawm = 37.84 ± 5.87 mM, edema = 54.69 ± 10.64 mM, gdce = 61.72 ± 12.95 mM, necrosis = 81.88 ± 17.53 mM) and the concentrations differed statistically significantly between all regarded areas (adjusted p-values for all pairwise comparisons < 0.05). Furthermore, IDH-mutated gliomas showed significantly higher 23Na concentrations than IDH wild-type gliomas (median [interquartile range]: IDH wild-type = 52.37 mM [45.98 - 58.56 mM], IDH mutated = 65.02 mM [58.87-67.05 mM], p = 0.039). Among the glioblastomas, there was a trend towards increased 23Na concentration in MGMT methylated tumors that did not reach statistical significance (median [interquartile range]: MGMT methylated = 57.59 mM [50.70 - 59.17 mM], MGMT not methylated = 48.78 mM [45.88 - 53.91 mM], p = 1.0). CONCLUSIONS 23Na MRI correlates with the IDH mutation status and could therefore enhance image guidance towards biopsy sites as wells as image-guided surgery and radiotherapy. Furthermore, the successive decrease of 23Na concentration from central necrosis to normal-appearing white matter suggests a correlation with tumor infiltration.
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Affiliation(s)
- Sebastian Regnery
- Department of Radiation Oncology, Heidelberg University Hospital, Im Neuenheimer Feld 400, 69120 Heidelberg, Germany; Clinical Cooperation Unit Radiation Oncology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Nicolas G R Behl
- Siemens Healthcare GmbH, Erlangen, Germany; Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Tanja Platt
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Nina Weinfurtner
- Division of Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Paul Windisch
- Department of Radiation Oncology, Heidelberg University Hospital, Im Neuenheimer Feld 400, 69120 Heidelberg, Germany
| | - Katerina Deike-Hofmann
- Division of Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Felix Sahm
- Department of Neuropathology, University Hospital Heidelberg, Im Neuenheimer Feld 224, 69120 Heidelberg, Germany; CCU Neuropathology, German Consortium for Translational Cancer Research, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Martin Bendszus
- Department of Neuroradiology, Heidelberg University Hospital, Im Neuenheimer Feld 400, 69120 Heidelberg, Germany
| | - Jürgen Debus
- Department of Radiation Oncology, Heidelberg University Hospital, Im Neuenheimer Feld 400, 69120 Heidelberg, Germany; Clinical Cooperation Unit Radiation Oncology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Mark E Ladd
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany; Faculty of Physics and Astronomy and Faculty of Medicine, University of Heidelberg, Heidelberg, Germany
| | - Heinz-Peter Schlemmer
- Division of Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Stefan Rieken
- Department of Radiation Oncology, Heidelberg University Hospital, Im Neuenheimer Feld 400, 69120 Heidelberg, Germany; Clinical Cooperation Unit Radiation Oncology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Sebastian Adeberg
- Department of Radiation Oncology, Heidelberg University Hospital, Im Neuenheimer Feld 400, 69120 Heidelberg, Germany; Clinical Cooperation Unit Radiation Oncology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Daniel Paech
- Division of Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany.
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Fortuin AS, Philips BWJ, van der Leest MMG, Ladd ME, Orzada S, Maas MC, Scheenen TWJ. Magnetic resonance imaging at ultra-high magnetic field strength: An in vivo assessment of number, size and distribution of pelvic lymph nodes. PLoS One 2020; 15:e0236884. [PMID: 32735614 PMCID: PMC7394386 DOI: 10.1371/journal.pone.0236884] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Accepted: 07/15/2020] [Indexed: 01/17/2023] Open
Abstract
Objective The definition of an in vivo nodal anatomical baseline is crucial for validation of representative lymph node dissections and accompanying pathology reports of pelvic cancers, as well as for assessing a potential therapeutic effect of extended lymph node dissections. Therefore the number, size and distribution of lymph nodes in the pelvis were assessed with high-resolution, large field-of-view, 7 Tesla (T) magnetic resonance imaging (MRI) with frequency-selective excitation. Materials and methods We used 7 T MRI for homogeneous pelvic imaging in 11 young healthy volunteers. Frequency-selective imaging of water and lipids was performed to detect nodal structures in the pelvis. Number and size of detected nodes was measured and size distribution per region was assessed. An average volunteer-normalized nodal size distribution was determined. Results In total, 564 lymph nodes were detected in six pelvic regions. Mean number was 51.3 with a wide range of 19–91 lymph nodes per volunteer. Mean diameter was 2.3 mm with a range of 1 to 7 mm. 69% Was 2 mm or smaller. The overall size distribution was very similar to the average volunteer-normalized nodal size distribution. Conclusions The amount of in vivo visible lymph nodes varies largely between subjects, whereas the normalized size distribution of nodes does not. The presence of many small lymph nodes (≤2mm) renders representative or complete removal of pelvic lymph nodes to be very difficult. 7T MRI may shift the in vivo detection limits of lymph node metastases in the future.
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Affiliation(s)
- Ansje S. Fortuin
- Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
- Department of Radiology, Ziekenhuis Gelderse Vallei, Ede, The Netherlands
| | - Bart W. J. Philips
- Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
| | | | - Mark E. Ladd
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Faculty of Physics and Astronomy and Faculty of Medicine, University of Heidelberg, Heidelberg, Germany
- Erwin L. Hahn Institute for Magnetic Resonance Imaging, Essen, Germany
| | - Stephan Orzada
- Erwin L. Hahn Institute for Magnetic Resonance Imaging, Essen, Germany
| | - Marnix C. Maas
- Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Tom W. J. Scheenen
- Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
- Erwin L. Hahn Institute for Magnetic Resonance Imaging, Essen, Germany
- * E-mail:
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50
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Straub S, Mangesius S, Emmerich J, Indelicato E, Nachbauer W, Degenhardt KS, Ladd ME, Boesch S, Gizewski ER. Toward quantitative neuroimaging biomarkers for Friedreich's ataxia at 7 Tesla: Susceptibility mapping, diffusion imaging, R 2 and R 1 relaxometry. J Neurosci Res 2020; 98:2219-2231. [PMID: 32731306 PMCID: PMC7590084 DOI: 10.1002/jnr.24701] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 06/12/2020] [Accepted: 07/08/2020] [Indexed: 01/21/2023]
Abstract
Friedreich's ataxia (FRDA) is a rare genetic disorder leading to degenerative processes. So far, no effective treatment has been found. Therefore, it is important to assist the development of medication with imaging biomarkers reflecting disease status and progress. Ten FRDA patients (mean age 37 ± 14 years; four female) and 10 age- and sex-matched controls were included. Acquisition of magnetic resonance imaging (MRI) data for quantitative susceptibility mapping, R1 , R2 relaxometry and diffusion imaging was performed at 7 Tesla. Results of volume of interest (VOI)-based analyses of the quantitative data were compared with a voxel-based morphometry (VBM) evaluation. Differences between patients and controls were assessed using the analysis of covariance (ANCOVA; p < 0.01) with age and sex as covariates, effect size of group differences, and correlations with disease characteristics with Spearman correlation coefficient. For the VBM analysis, a statistical threshold of 0.001 for uncorrected and 0.05 for corrected p-values was used. Statistically significant differences between FRDA patients and controls were found in five out of twelve investigated structures, and statistically significant correlations with disease characteristics were revealed. Moreover, VBM revealed significant white matter atrophy within regions of the brainstem, and the cerebellum. These regions overlapped partially with brain regions for which significant differences between healthy controls and patients were found in the VOI-based quantitative MRI evaluation. It was shown that two independent analyses provided overlapping results. Moreover, positive results on correlations with disease characteristics were found, indicating that these quantitative MRI parameters could provide more detailed information and assist the search for effective treatments.
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Affiliation(s)
- Sina Straub
- Division of Medical Physics, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Stephanie Mangesius
- Department of Neuroradiology, Medical University of Innsbruck, Innsbruck, Austria.,Neuroimaging Core Facility, Medical University of Innsbruck, Innsbruck, Austria
| | - Julian Emmerich
- Division of Medical Physics, German Cancer Research Center (DKFZ), Heidelberg, Germany.,Faculty of Physics and Astronomy, Heidelberg University, Heidelberg, Germany
| | | | - Wolfgang Nachbauer
- Department of Neurology, Medical University of Innsbruck, Innsbruck, Austria
| | - Katja S Degenhardt
- Division of Medical Physics, German Cancer Research Center (DKFZ), Heidelberg, Germany.,Faculty of Physics and Astronomy, Heidelberg University, Heidelberg, Germany
| | - Mark E Ladd
- Division of Medical Physics, German Cancer Research Center (DKFZ), Heidelberg, Germany.,Faculty of Physics and Astronomy, Heidelberg University, Heidelberg, Germany.,Faculty of Medicine, Heidelberg University, Heidelberg, Germany
| | - Sylvia Boesch
- Department of Neurology, Medical University of Innsbruck, Innsbruck, Austria
| | - Elke R Gizewski
- Department of Neuroradiology, Medical University of Innsbruck, Innsbruck, Austria.,Neuroimaging Core Facility, Medical University of Innsbruck, Innsbruck, Austria
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