1
|
de Alba Alvarez I, Arbabi A, Khlebnikov V, Marques JP, Norris DG. Single-shot frequency offset measurement with HASTE using the selective parity approach. Sci Rep 2024; 14:9949. [PMID: 38688948 PMCID: PMC11061157 DOI: 10.1038/s41598-024-60275-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Accepted: 04/21/2024] [Indexed: 05/02/2024] Open
Abstract
Measurements of frequency offset are commonly required in MRI. The standard method measures the signal phase as a function of evolution time. Here we use a single shot turbo-spin-echo acquisition method to measure frequency offset at a single evolution time. After excitation the transverse magnetisation evolves during the evolution time, and is then repeatedly refocused. The phase is conjugated between alternate echoes. Using partial parallel acquisition techniques we obtain separate odd- and even- echo images. An iterative procedure ensures self-consistency between them. The difference in phase between the two images yields frequency offset maps. The technique was implemented at 3 Tesla and tested on a healthy human volunteer for a range of evolution times between 6 and 42 ms. A standard method using a similar readout train and multiple evolution times was used as a gold-standard measure. In a statistical comparison with the gold standard no evidence for bias or offset was found. There was no systematic variation in precision or accuracy as a function of evolution time. We conclude that the presented approach represents a viable method for the rapid generation of frequency offset maps with a high image quality and minimal distortion.
Collapse
Affiliation(s)
- Irina de Alba Alvarez
- Donders Institute for Brain, Cognition and Behaviour, Centre for Cognitive Neuroimaging, Radboud University, Nijmegen, The Netherlands
- Multi-Modality Medical Imaging (M3I), Faculty of Science and Technology, University of Twente, Enschede, Netherlands
| | - Aidin Arbabi
- Donders Institute for Brain, Cognition and Behaviour, Centre for Cognitive Neuroimaging, Radboud University, Nijmegen, The Netherlands
| | - Vitaliy Khlebnikov
- Donders Institute for Brain, Cognition and Behaviour, Centre for Cognitive Neuroimaging, Radboud University, Nijmegen, The Netherlands
| | - José P Marques
- Donders Institute for Brain, Cognition and Behaviour, Centre for Cognitive Neuroimaging, Radboud University, Nijmegen, The Netherlands
| | - David G Norris
- Donders Institute for Brain, Cognition and Behaviour, Centre for Cognitive Neuroimaging, Radboud University, Nijmegen, The Netherlands.
- Erwin L. Hahn Institute for Magnetic Resonance Imaging UNESCO World Cultural Heritage Zollverein, Kokereiallee 7, Building C84, 45141, Essen, Germany.
- Department of Clinical Neurophysiology (CNPH), Faculty Science and Technology, University of Twente, Enschede, The Netherlands.
| |
Collapse
|
2
|
Herrmann CJJ, Els A, Boehmert L, Periquito J, Eigentler TW, Millward JM, Waiczies S, Kuchling J, Paul F, Niendorf T. Simultaneous T 2 and T 2 ∗ mapping of multiple sclerosis lesions with radial RARE-EPI. Magn Reson Med 2021; 86:1383-1402. [PMID: 33951214 DOI: 10.1002/mrm.28811] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 03/26/2021] [Accepted: 03/26/2021] [Indexed: 12/26/2022]
Abstract
PURPOSE The characteristic MRI features of multiple sclerosis (MS) lesions make it conceptually appealing to pursue parametric mapping techniques that support simultaneous generation of quantitative maps of 2 or more MR contrast mechanisms. We present a modular rapid acquisition with relaxation enhancement (RARE)-EPI hybrid that facilitates simultaneous T2 and T 2 ∗ mapping (2in1-RARE-EPI). METHODS In 2in1-RARE-EPI the first echoes in the echo train are acquired with a RARE module, later echoes are acquired with an EPI module. To define the fraction of echoes covered by the RARE and EPI module, an error analysis of T2 and T 2 ∗ was conducted with Monte Carlo simulations. Radial k-space (under)sampling was implemented for acceleration (R = 2). The feasibility of 2in1-RARE-EPI for simultaneous T2 and T 2 ∗ mapping was examined in a phantom study mimicking T2 and T 2 ∗ relaxation times of the brain. For validation, 2in1-RARE-EPI was benchmarked versus multi spin-echo (MSE) and multi gradient-echo (MGRE) techniques. The clinical applicability of 2in1-RARE-EPI was demonstrated in healthy subjects and MS patients. RESULTS There was a good agreement between T2 / T 2 ∗ values derived from 2in1-RARE-EPI and T2 / T 2 ∗ reference values obtained from MSE and MGRE in both phantoms and healthy subjects. In patients, MS lesions in T2 and T 2 ∗ maps deduced from 2in1-RARE-EPI could be just as clearly delineated as in reference maps calculated from MSE/MGRE. CONCLUSION This work demonstrates the feasibility of radially (under)sampled 2in1-RARE-EPI for simultaneous T2 and T 2 ∗ mapping in MS patients.
Collapse
Affiliation(s)
- Carl J J Herrmann
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany.,Department of Physics, Humboldt University of Berlin, Berlin, Germany
| | - Antje Els
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Laura Boehmert
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Joao Periquito
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Thomas Wilhelm Eigentler
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany.,Chair of Medical Engineering, Technical University of Berlin, Berlin, Germany
| | - Jason M Millward
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Sonia Waiczies
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Joseph Kuchling
- Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine, Berlin, Germany.,NeuroCure Clinical Research Center, Charité-Universitätsmedizin, Berlin, Germany.,Department of Neurology, Charité-Universitätsmedizin, Berlin, Germany
| | - Friedemann Paul
- Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine, Berlin, Germany.,NeuroCure Clinical Research Center, Charité-Universitätsmedizin, Berlin, Germany.,Department of Neurology, Charité-Universitätsmedizin, Berlin, Germany
| | - Thoralf Niendorf
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany.,Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine, Berlin, Germany
| |
Collapse
|
3
|
Ji Y, Winter L, Navarro L, Ku MC, Periquito JS, Pham M, Hoffmann W, Theune LE, Calderón M, Niendorf T. Controlled Release of Therapeutics from Thermoresponsive Nanogels: A Thermal Magnetic Resonance Feasibility Study. Cancers (Basel) 2020; 12:cancers12061380. [PMID: 32471299 PMCID: PMC7352924 DOI: 10.3390/cancers12061380] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 05/23/2020] [Accepted: 05/25/2020] [Indexed: 12/16/2022] Open
Abstract
Thermal magnetic resonance (ThermalMR) accommodates radio frequency (RF)-induced temperature modulation, thermometry, anatomic and functional imaging, and (nano)molecular probing in an integrated RF applicator. This study examines the feasibility of ThermalMR for the controlled release of a model therapeutics from thermoresponsive nanogels using a 7.0-tesla whole-body MR scanner en route to local drug-delivery-based anticancer treatments. The capacity of ThermalMR is demonstrated in a model system involving the release of fluorescein-labeled bovine serum albumin (BSA-FITC, a model therapeutic) from nanometer-scale polymeric networks. These networks contain thermoresponsive polymers that bestow environmental responsiveness to physiologically relevant changes in temperature. The release profile obtained for the reference data derived from a water bath setup used for temperature stimulation is in accordance with the release kinetics deduced from the ThermalMR setup. In conclusion, ThermalMR adds a thermal intervention dimension to an MRI device and provides an ideal testbed for the study of the temperature-induced release of drugs, magnetic resonance (MR) probes, and other agents from thermoresponsive carriers. Integrating diagnostic imaging, temperature intervention, and temperature response control, ThermalMR is conceptually appealing for the study of the role of temperature in biology and disease and for the pursuit of personalized therapeutic drug delivery approaches for better patient care.
Collapse
Affiliation(s)
- Yiyi Ji
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbruck Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin, Germany; (Y.J.); (M.-C.K.); (J.S.P.); (M.P.)
| | - Lukas Winter
- Physikalisch-Technische Bundesanstalt (PTB), 10587 Berlin, Germany; (L.W.); (W.H.)
| | - Lucila Navarro
- Freie Universität Berlin, Institute of Chemistry and Biochemistry, 14195 Berlin, Germany; (L.N.); (L.E.T.); (M.C.)
- Instituto de Desarrollo Tecnológico para la Industria Química (INTEC), Universidad Nacional del Litoral (UNL)—Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Santa Fe 3000, Argentina
| | - Min-Chi Ku
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbruck Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin, Germany; (Y.J.); (M.-C.K.); (J.S.P.); (M.P.)
| | - João S. Periquito
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbruck Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin, Germany; (Y.J.); (M.-C.K.); (J.S.P.); (M.P.)
| | - Michal Pham
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbruck Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin, Germany; (Y.J.); (M.-C.K.); (J.S.P.); (M.P.)
| | - Werner Hoffmann
- Physikalisch-Technische Bundesanstalt (PTB), 10587 Berlin, Germany; (L.W.); (W.H.)
| | - Loryn E. Theune
- Freie Universität Berlin, Institute of Chemistry and Biochemistry, 14195 Berlin, Germany; (L.N.); (L.E.T.); (M.C.)
| | - Marcelo Calderón
- Freie Universität Berlin, Institute of Chemistry and Biochemistry, 14195 Berlin, Germany; (L.N.); (L.E.T.); (M.C.)
- POLYMAT and Applied Chemistry Department, Faculty of Chemistry, University of the Basque Country UPV/EHU, 20018 Donostia-San Sebastián, Spain
- IKERBASQUE, Basque Foundation for Science, 48013 Bilbao, Spain
| | - Thoralf Niendorf
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbruck Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin, Germany; (Y.J.); (M.-C.K.); (J.S.P.); (M.P.)
- Experimental and Clinical Research Center (ECRC), a joint cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine, 13125 Berlin, Germany
- Correspondence: ; Tel.: +49-30-9406-4505
| |
Collapse
|
4
|
Lorio S, Tierney TM, McDowell A, Arthurs OJ, Lutti A, Weiskopf N, Carmichael DW. Flexible proton density (PD) mapping using multi-contrast variable flip angle (VFA) data. Neuroimage 2018; 186:464-475. [PMID: 30465865 DOI: 10.1016/j.neuroimage.2018.11.023] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 11/13/2018] [Accepted: 11/16/2018] [Indexed: 12/13/2022] Open
Abstract
Quantitative proton density (PD) maps measure the amount of free water, which is important for non-invasive tissue characterization in pathology and across lifespan. PD mapping requires the estimation and subsequent removal of factors influencing the signal intensity other than PD. These factors include the T1, T2* relaxation effects, transmit field inhomogeneities, receiver coil sensitivity profile (RP) and the spatially invariant factor that is required to scale the data. While the transmit field can be reliably measured, the RP estimation is usually based on image post-processing techniques due to limitations of its measurement at magnetic fields higher than 1.5 T. The post-processing methods are based on unified bias-field/tissue segmentation, fitting the sensitivity profile from images obtained with different coils, or on the linear relationship between T1 and PD. The scaling factor is derived from the signal within a specific tissue compartment or reference object. However, these approaches for calculating the RP and scaling factor have limitations particularly in severe pathology or over a wide age range, restricting their application. We propose a new approach for PD mapping based on a multi-contrast variable flip angle acquisition protocol and a data-driven estimation method for the RP correction and map scaling. By combining all the multi-contrast data acquired at different echo times, we are able to fully correct the MRI signal for T2* relaxation effects and to decrease the variance and the entropy of PD values within tissue class of the final map. The RP is determined from the corrected data applying a non-parametric bias estimation, and the scaling factor is based on the median intensity of an external calibration object. Finally, we compare the signal intensity and homogeneity of the multi-contrast PD map with the well-established effective PD (PD*) mapping, for which the RP is based on concurrent bias field estimation and tissue classification, and the scaling factor is estimated from the mean white matter signal. The multi-contrast PD values homogeneity and accuracy within the cerebrospinal fluid (CSF) and deep brain structures are increased beyond that obtained using PD* maps. We demonstrate that the multi-contrast RP approach is insensitive to anatomical or a priori tissue information by applying it in a patient with extensive brain abnormalities and for whole body PD mapping in post-mortem foetal imaging.
Collapse
Affiliation(s)
- Sara Lorio
- UCL Great Ormond Street Institute of Child Health, University College London, London, UK.
| | - Tim M Tierney
- Wellcome Centre for Human Neuroimaging, UCL Institute of Neurology, University College London, London, UK
| | - Amy McDowell
- UCL Great Ormond Street Institute of Child Health, University College London, London, UK
| | - Owen J Arthurs
- UCL Great Ormond Street Institute of Child Health, University College London, London, UK; Department of Radiology, Great Ormond Street Hospital for Children, London, UK
| | - Antoine Lutti
- Laboratory for Research in Neuroimaging, Department of Clinical Neuroscience, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Nikolaus Weiskopf
- Department of Neurophysics, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - David W Carmichael
- UCL Great Ormond Street Institute of Child Health, University College London, London, UK; EPSRC / Wellcome Centre for Medical Engineering, Biomedical Engineering, King's College, London, UK
| |
Collapse
|
5
|
Pohlmann A, Cantow K, Huelnhagen T, Grosenick D, Dos Santos Periquito J, Boehmert L, Gladytz T, Waiczies S, Flemming B, Seeliger E, Niendorf T. Experimental MRI Monitoring of Renal Blood Volume Fraction Variations En Route to Renal Magnetic Resonance Oximetry. ACTA ACUST UNITED AC 2017; 3:188-200. [PMID: 30042981 PMCID: PMC6024389 DOI: 10.18383/j.tom.2017.00012] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Diagnosis of early-stage acute kidney injury (AKI) will benefit from a timely identification of local tissue hypoxia. Renal tissue hypoxia is an early feature in AKI pathophysiology, and renal oxygenation is increasingly being assessed through T2*-weighted magnetic resonance imaging (MRI). However, changes in renal blood volume fraction (BVf) confound renal T2*. The aim of this study was to assess the feasibility of intravascular contrast-enhanced MRI for monitoring renal BVf during physiological interventions that are concomitant with variations in BVf and to explore the possibility of correcting renal T2* for BVf variations. A dose-dependent study of the contrast agent ferumoxytol was performed in rats. BVf was monitored throughout short-term occlusion of the renal vein, which is known to markedly change renal blood partial pressure of O2 and BVf. BVf calculated from MRI measurements was used to estimate oxygen saturation of hemoglobin (SO2). BVf and SO2 were benchmarked against cortical data derived from near-infrared spectroscopy. As estimated from magnetic resonance parametric maps of T2 and T2*, BVf was shown to increase, whereas SO2 was shown to decline during venous occlusion (VO). This observation could be quantitatively reproduced in test–retest scenarios. Changes in BVf and SO2 were in good agreement with data obtained from near-infrared spectroscopy. Our findings provide motivation to advance multiparametric MRI for studying AKIs, with the ultimate goal of translating MRI-based renal BVf mapping into clinical practice en route noninvasive renal magnetic resonance oximetry as a method of assessing AKI and progression to chronic damage.
Collapse
Affiliation(s)
- Andreas Pohlmann
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin Ultrahigh Field Facility (B.U.F.F.), Berlin, Germany
| | - Kathleen Cantow
- Institute of Physiology and Center for Cardiovascular Research, Charité - Universitätsmedizin Berlin, Campus Charité Mitte, Berlin, Germany
| | - Till Huelnhagen
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin Ultrahigh Field Facility (B.U.F.F.), Berlin, Germany
| | - Dirk Grosenick
- Physikalisch-Technische-Bundesanstalt (PTB), Berlin, Germany
| | - Joāo Dos Santos Periquito
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin Ultrahigh Field Facility (B.U.F.F.), Berlin, Germany
| | - Laura Boehmert
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin Ultrahigh Field Facility (B.U.F.F.), Berlin, Germany
| | - Thomas Gladytz
- Physikalisch-Technische-Bundesanstalt (PTB), Berlin, Germany
| | - Sonia Waiczies
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin Ultrahigh Field Facility (B.U.F.F.), Berlin, Germany
| | - Bert Flemming
- Institute of Physiology and Center for Cardiovascular Research, Charité - Universitätsmedizin Berlin, Campus Charité Mitte, Berlin, Germany
| | - Erdmann Seeliger
- Institute of Physiology and Center for Cardiovascular Research, Charité - Universitätsmedizin Berlin, Campus Charité Mitte, Berlin, Germany
| | - Thoralf Niendorf
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin Ultrahigh Field Facility (B.U.F.F.), Berlin, Germany.,Experimental and Clinical Research Center, Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany; and.,Deutsches Zentrum für Herz- Kreislauf-Forschung (DZHK; German Centre for Cardiovascular Research), Berlin, Germany
| |
Collapse
|
6
|
Niendorf T, Paul K, Oezerdem C, Graessl A, Klix S, Huelnhagen T, Hezel F, Rieger J, Waiczies H, Frahm J, Nagel AM, Oberacker E, Winter L. W(h)ither human cardiac and body magnetic resonance at ultrahigh fields? technical advances, practical considerations, applications, and clinical opportunities. NMR IN BIOMEDICINE 2016; 29:1173-97. [PMID: 25706103 DOI: 10.1002/nbm.3268] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Revised: 12/26/2014] [Accepted: 01/13/2015] [Indexed: 05/12/2023]
Abstract
The objective of this study was to document and review advances and groundbreaking progress in cardiac and body MR at ultrahigh fields (UHF, B0 ≥ 7.0 T) with the goal to attract talent, clinical adopters, collaborations and resources to the biomedical and diagnostic imaging communities. This review surveys traits, advantages and challenges of cardiac and body MR at 7.0 T. The considerations run the gamut from technical advances to clinical opportunities. Key concepts, emerging technologies, practical considerations, frontier applications and future directions of UHF body and cardiac MR are provided. Examples of UHF cardiac and body imaging strategies are demonstrated. Their added value over the kindred counterparts at lower fields is explored along with an outline of research promises. The achievements of cardiac and body UHF-MR are powerful motivators and enablers, since extra speed, signal and imaging capabilities may be invested to overcome the fundamental constraints that continue to hamper traditional cardiac and body MR applications. If practical obstacles, concomitant physics effects and technical impediments can be overcome in equal measure, sophisticated cardiac and body UHF-MR will help to open the door to new MRI and MRS approaches for basic research and clinical science, with the lessons learned at 7.0 T being transferred into broad clinical use including diagnostics and therapy guiding at lower fields. Copyright © 2015 John Wiley & Sons, Ltd.
Collapse
Affiliation(s)
- Thoralf Niendorf
- Berlin Ultrahigh Field Facility (BUFF), Max-Delbrueck Center for Molecular Medicine, Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site, Berlin, Germany
| | - Katharina Paul
- Berlin Ultrahigh Field Facility (BUFF), Max-Delbrueck Center for Molecular Medicine, Berlin, Germany
| | - Celal Oezerdem
- Berlin Ultrahigh Field Facility (BUFF), Max-Delbrueck Center for Molecular Medicine, Berlin, Germany
| | - Andreas Graessl
- Berlin Ultrahigh Field Facility (BUFF), Max-Delbrueck Center for Molecular Medicine, Berlin, Germany
| | - Sabrina Klix
- Berlin Ultrahigh Field Facility (BUFF), Max-Delbrueck Center for Molecular Medicine, Berlin, Germany
| | - Till Huelnhagen
- Berlin Ultrahigh Field Facility (BUFF), Max-Delbrueck Center for Molecular Medicine, Berlin, Germany
| | - Fabian Hezel
- Berlin Ultrahigh Field Facility (BUFF), Max-Delbrueck Center for Molecular Medicine, Berlin, Germany
| | | | | | - Jens Frahm
- Biomedizinische NMR Forschungs GmbH, am Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site, Göttingen, Germany
| | - Armin M Nagel
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Eva Oberacker
- Berlin Ultrahigh Field Facility (BUFF), Max-Delbrueck Center for Molecular Medicine, Berlin, Germany
| | - Lukas Winter
- Berlin Ultrahigh Field Facility (BUFF), Max-Delbrueck Center for Molecular Medicine, Berlin, Germany
| |
Collapse
|
7
|
Do WJ, Kim KH, Choi SH, Park SH. Artifact-suppressed optimal three-dimensional T 1 - and T 2 *-weighted dual-echo imaging. Magn Reson Med 2015; 76:1504-1511. [PMID: 26536831 DOI: 10.1002/mrm.26033] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Revised: 10/13/2015] [Accepted: 10/14/2015] [Indexed: 11/05/2022]
Abstract
PURPOSE To develop a new artifact-suppressed optimal three-dimensional (3D) T1 - and T2 *-weighted dual-echo imaging. METHODS We optimized flip angles for 3D T1 - and T2 *-weighted imaging by conventional dual-echo in vivo experiments and computer simulations, and then implemented a dual-echo sequence with an echo-specific k-space reordering scheme to satisfy the optimal flip angles for both T1 and T2 * contrast. We also proposed two strategies to suppress ringing artifacts induced by the abrupt flip angle jumps in the proposed dual echo sequence: (i) implementing smooth transition regions and (ii) discarding the k-space regions of the abrupt flip angle jumps as dummy phase-encoding steps. RESULTS The optimal flip angles measured from experiments were different between T1 - and T2 *-weighted contrast, in agreement with simulations. The echo-specific k-space reordered dual-echo sequence showed optimal T1 and T2 * contrast simultaneously, but also showed ringing artifacts because of high flip-angle changes between k-space regions. The two proposed strategies effectively suppressed the ringing artifacts. CONCLUSION The proposed 3D dual-echo sequence provided optimal T1 and T2 * contrast simultaneously with no artifacts and thus is potentially applicable to routine clinical applications for simultaneous high resolution T1 - and T2 *-weighted imaging. Magn Reson Med 76:1504-1511, 2016. © 2015 International Society for Magnetic Resonance in Medicine.
Collapse
Affiliation(s)
- Won-Joon Do
- MRI Laboratory, Department of Bio and Brian Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea
| | - Ki Hwan Kim
- MRI Laboratory, Department of Bio and Brian Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea.,Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon, South Korea
| | - Seung Hong Choi
- Department of Radiology, Seoul National University College of Medicine, Seoul, Korea
| | - Sung-Hong Park
- MRI Laboratory, Department of Bio and Brian Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea.
| |
Collapse
|
8
|
Diffusion-Sensitized Ophthalmic Magnetic Resonance Imaging Free of Geometric Distortion at 3.0 and 7.0 T. Invest Radiol 2015; 50:309-21. [DOI: 10.1097/rli.0000000000000129] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
|
9
|
Klix S, Hezel F, Fuchs K, Ruff J, Dieringer MA, Niendorf T. Accelerated fast spin-echo magnetic resonance imaging of the heart using a self-calibrated split-echo approach. PLoS One 2014; 9:e94654. [PMID: 24728341 PMCID: PMC3984237 DOI: 10.1371/journal.pone.0094654] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2013] [Accepted: 03/19/2014] [Indexed: 12/18/2022] Open
Abstract
Purpose Design, validation and application of an accelerated fast spin-echo (FSE) variant that uses a split-echo approach for self-calibrated parallel imaging. Methods For self-calibrated, split-echo FSE (SCSE-FSE), extra displacement gradients were incorporated into FSE to decompose odd and even echo groups which were independently phase encoded to derive coil sensitivity maps, and to generate undersampled data (reduction factor up to R = 3). Reference and undersampled data were acquired simultaneously. SENSE reconstruction was employed. Results The feasibility of SCSE-FSE was demonstrated in phantom studies. Point spread function performance of SCSE-FSE was found to be competitive with traditional FSE variants. The immunity of SCSE-FSE for motion induced mis-registration between reference and undersampled data was shown using a dynamic left ventricular model and cardiac imaging. The applicability of black blood prepared SCSE-FSE for cardiac imaging was demonstrated in healthy volunteers including accelerated multi-slice per breath-hold imaging and accelerated high spatial resolution imaging. Conclusion SCSE-FSE obviates the need of external reference scans for SENSE reconstructed parallel imaging with FSE. SCSE-FSE reduces the risk for mis-registration between reference scans and accelerated acquisitions. SCSE-FSE is feasible for imaging of the heart and of large cardiac vessels but also meets the needs of brain, abdominal and liver imaging.
Collapse
Affiliation(s)
- Sabrina Klix
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrueck-Center for Molecular Medicine, Berlin, Germany
| | - Fabian Hezel
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrueck-Center for Molecular Medicine, Berlin, Germany
| | - Katharina Fuchs
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrueck-Center for Molecular Medicine, Berlin, Germany
| | - Jan Ruff
- Siemens Healthcare, Erlangen, Germany
| | - Matthias A. Dieringer
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrueck-Center for Molecular Medicine, Berlin, Germany
- Experimental and Clinical Research Center (ECRC), a joint cooperation between the Charité Medical Faculty and the Max-Delbrueck-Center for Molecular Medicine, Berlin, Germany
| | - Thoralf Niendorf
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrueck-Center for Molecular Medicine, Berlin, Germany
- * E-mail:
| |
Collapse
|