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Haber-Pohlmeier S, Caterina D, Blümich B, Pohlmeier A. Magnetic Resonance Imaging of Water Content and Flow Processes in Natural Soils by Pulse Sequences with Ultrashort Detection. Molecules 2021; 26:molecules26175130. [PMID: 34500563 PMCID: PMC8433766 DOI: 10.3390/molecules26175130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 08/16/2021] [Accepted: 08/17/2021] [Indexed: 11/17/2022] Open
Abstract
Magnetic resonance imaging is a valuable tool for three-dimensional mapping of soil water processes due to its sensitivity to the substance of interest: water. Since conventional gradient- or spin-echo based pulse sequences do not detect rapidly relaxing fractions of water in natural porous media with transverse relaxation times in the millisecond range, pulse sequences with ultrafast detection open a way out. In this work, we compare a spin-echo multislice pulse sequence with ultrashort (UTE) and zero-TE (ZTE) sequences for their suitability to map water content and its changes in 3D in natural soil materials. Longitudinal and transverse relaxation times were found in the ranges around 80 ms and 1 to 50 ms, respectively, so that the spin echo sequence misses larger fractions of water. In contrast, ZTE and UTE could detect all water, if the excitation and detection bandwidths were set sufficiently broad. More precisely, with ZTE we could map water contents down to 0.1 cm3/cm3. Finally, we employed ZTE to monitor the development of film flow in a natural soil core with high temporal resolution. This opens the route for further quantitative imaging of soil water processes.
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Affiliation(s)
- Sabina Haber-Pohlmeier
- Institute for Modelling Hydraulic and Environmental Systems, University of Stuttgart, Pfaffenwaldring 61, D-70569 Stuttgart, Germany;
| | - David Caterina
- Institute for Bio- and Geosciences Agrosphere (IBG-3), Research Center Jülich, D-52425 Jülich, Germany;
- Département UEE, Faculté des Sciences Appliquées, Université de Liège, B-4000 Liège, Belgium
| | - Bernhard Blümich
- Institute for Technical and Macromolecular Chemistry, RWTH Aachen University, Worringer Weg 2, D-52074 Aachen, Germany;
| | - Andreas Pohlmeier
- Institute for Bio- and Geosciences Agrosphere (IBG-3), Research Center Jülich, D-52425 Jülich, Germany;
- Correspondence:
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Afrough A. Magnetic resonance free induction decay in geological porous materials. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2021; 44:107. [PMID: 34417887 DOI: 10.1140/epje/s10189-021-00110-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 08/02/2021] [Indexed: 06/13/2023]
Abstract
Magnetic resonance is an important noninvasive technology across life sciences and industry. Free induction decay is the simplest [Formula: see text]H magnetic resonance measurement method and an important means of probing fast-decaying signals in porous materials such as rocks, lung, and bone. It is commonly assumed that the free induction decay in geological porous materials is single-exponential. We experimentally observed two regimes of free induction decay behavior in geological porous materials: single-exponential and non-exponential decay. Numerical simulations that match experimental data highlight the effect of mass diffusion, especially in the single-exponential behavior. These two regimes of free induction decay in porous materials are associated with a bifurcation point in the solutions of the Bloch-Torrey equation for diffusion of fluids in confined domains in the presence of internal magnetic field gradients. This finding facilitates the extraction of absolute internal magnetic field gradient intensities from simple free induction decay measurements in the laboratory and field. This work also warns against common single-exponential assumptions in surface magnetic resonance methods employed in surveying underground water aquifers.
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Affiliation(s)
- Armin Afrough
- Danish Hydrocarbon Research and Technology Centre, Technical University of Denmark, Elektrovej, Kongens Lyngby, Denmark.
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Evrard L, Joostens Z, Vandersmissen M, Audigié F, Busoni V. Comparison Between Ultrasonographic and Standing Magnetic Resonance Imaging Findings in the Podotrochlear Apparatus of Horses With Foot Pain. Front Vet Sci 2021; 8:675180. [PMID: 34291100 PMCID: PMC8287171 DOI: 10.3389/fvets.2021.675180] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 05/24/2021] [Indexed: 11/13/2022] Open
Abstract
This prospective study aimed to blindly compare the ultrasonographic and standing magnetic resonance imaging (sMRI) findings in deep digital flexor tendon (DDFT), navicular bone, and navicular bursa in horses with foot pain, positive digital analgesia, and without definitive radiographic diagnosis. Ultrasonography detected more DDFT abnormalities (32/34 feet vs. 27/34 with sMRI) but identified less palmar navicular abnormalities (23/34 feet vs. 30/34 with sMRI). In suprasesamoidean DDFT lesions, which were mainly dorsally located, changes in echogenicity did not correspond to a particular pattern of sMRI signal change. Transcuneal ultrasonography did not allow assessment of morphology and extent of distal DDFT lesions, and sporadically discriminated the affected lobe compared to sMRI. Defects of the palmar compact bone were identified with both modalities except a parasagittal defect, which was only seen at sMRI.
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Affiliation(s)
- Laurence Evrard
- Department of Clinical Sciences of Companion Animals and Equids, Equine Division, Diagnostic Imaging Section, University of Liège, Liège, Belgium
| | - Zoë Joostens
- Medical Imaging Department, Equitom Equine Clinic, Lummen, Belgium
| | - Maxime Vandersmissen
- Department of Clinical Sciences of Companion Animals and Equids, Equine Division, Diagnostic Imaging Section, University of Liège, Liège, Belgium
| | - Fabrice Audigié
- Centre d'Imagerie et de Recherche sur les Affections Locomotrices Equines, Ecole Nationale Vétérinaire d'Alfort, Goustranville, France
| | - Valeria Busoni
- Department of Clinical Sciences of Companion Animals and Equids, Equine Division, Diagnostic Imaging Section, University of Liège, Liège, Belgium
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Ozen AC, Idiyatullin D, Adriany G, Jungst S, Kobayashi N, Groenke BR, Bock M, Garwood M, Nixdorf DR. Design of an Intraoral Dipole Antenna for Dental Applications. IEEE Trans Biomed Eng 2021; 68:2563-2573. [PMID: 33513097 DOI: 10.1109/tbme.2021.3055777] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
OBJECTIVE In dental MRI, intraoral coils provide higher signal-to-noise ratio (SNR) than coils placed outside the mouth. This study aims to design an intraoral dipole antenna and demonstrates the feasibility of combining it with an extraoral coil. METHODS Dipole antenna design was chosen over loop design, as it is open toward the distal; therefore, it does not restrain tongue movement. The dipole design offers also an increased depth-of-sensitivity that allows for MRI of dental roots. Different dipole antenna designs were simulated using a finite-difference-time-domain approach. Ribbon, wire, and multi-wire arms were compared. The best design was improved further by covering the ends of the dipole arms with a high-permittivity material. Phantom and in vivo measurements were conducted on a 3T clinical MRI system. RESULTS The best transmit efficiency and homogeneity was achieved with a multi-wire curved dipole antenna with 7 wires for each arm. With an additional high-permittivity cap the transmit field inhomogeneity was further reduced from 20% to 5% along the dipole arm. When combined with extraoral flexible surface-coil, the coupling between the coils was less than -32dB and SNR was increased. CONCLUSION Using intraoral dipole design instead of loop improves patient comfort. We demonstrated feasibility of the intraoral dipole combined with an extraoral flexible coil-array for dental MRI. Dipole antenna enabled decreasing imaging field-of-view, and reduced the prevalent signal from tongue. SIGNIFICANCE This study highlights the advantages and the main challenges of the intraoral RF coils and describes a novel RF coil that addresses those challenges.
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Ahmadian S, Jabbari I, Bagherimofidi SM, Saligheh Rad H. Characterization of hardware-related spatial distortions for IR-PETRA pulse sequence using a brain specific phantom. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2020; 34:213-228. [PMID: 32632747 DOI: 10.1007/s10334-020-00863-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 06/22/2020] [Accepted: 06/24/2020] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Inversion recovery-pointwise encoding time reduction with radial acquisition (IR-PETRA) is an effective magnetic resonance (MR) pulse sequence in generating pseudo-CTs. The hardware-related spatial-distortion (HRSD) in MR images potentially deteriorates the accuracy of pseudo-CTs. Thus, we aimed at characterizing HRSD for IR-PETRA. MATERIALS AND METHODS gross-HRSDoverall (Euclidean-sum of gross-HRSDi (i = x, y, z)) for IR-PETRA was assessed using a brain-specific phantom for two MR scanners (1.5 T-Aera and 3.0 T-Prisma). Moreover, hardware imperfections were analyzed by determining gradient-nonlinearity spatial-distortion (GNSD) and B0-inhomogeneity spatial-distortion (B0ISD) for magnetization-prepared rapid acquisition gradient-echo (MP-RAGE) which has well-known distortion characteristics. RESULTS In 3.0 T, maximum of gross-GNSDoverall (Euclidean-sum of gross-GNSDi) and gross-B0ISD for MP-RAGE was 2.77 mm and 0.57 mm, respectively. For this scanner, the mean and maximum of gross-HRSDoverall for IR-PETRA were 0.63 ± 0.38 mm and 1.91 mm, respectively. In 1.5 T, maximum of gross-GNSDoverall and gross-B0ISD for MP-RAGE was 3.41 mm and 0.78 mm, respectively. The mean and maximum of gross-HRSDoverall for IR-PETRA were 1.02 ± 0.50 mm and 3.12 mm, respectively. DISCUSSION The spatial accuracy of MR images, besides being impacted by hardware performance, scanner capabilities, and imaging parameters, is mainly affected by its imaging strategy and data acquisition scheme. In 3.0 T, even without applying vendor correction algorithms, spatial accuracy of IR-PETRA image is sufficient for generating pseudo-CTs. In 1.5 T, distortion-correction is required to provide this accuracy.
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Affiliation(s)
- Sima Ahmadian
- Faculty of Advanced Sciences and Technologies, University of Isfahan, Isfahan, Iran
| | - Iraj Jabbari
- Faculty of Advanced Sciences and Technologies, University of Isfahan, Isfahan, Iran.
| | - Seyed Mehdi Bagherimofidi
- Department of Biomedical Engineering, Aliabad Katoul Branch, Islamic Azad University, Aliabad-e-Katoul, Iran
| | - Hamidreza Saligheh Rad
- Quantitative MR Imaging and Spectroscopy Group, Research Center for Molecular and Cellular Imaging, Tehran University of Medical Sciences, Tehran, Iran
- Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran, Iran
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Bae K, Jeon KN, Hwang MJ, Lee JS, Park SE, Kim HC, Menini A. Respiratory motion-resolved four-dimensional zero echo time (4D ZTE) lung MRI using retrospective soft gating: feasibility and image quality compared with 3D ZTE. Eur Radiol 2020; 30:5130-5138. [PMID: 32333146 DOI: 10.1007/s00330-020-06890-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Revised: 03/18/2020] [Accepted: 04/10/2020] [Indexed: 12/11/2022]
Abstract
OBJECTIVES To evaluate the feasibility and image quality of respiratory motion-resolved 4D zero echo time (ZTE) lung MRI compared with that of 3D ZTE. METHODS Our institutional review board approved this study. Twenty-one patients underwent lung scans using 3D ZTE and 4D ZTE sequences via prospective and retrospective soft gating techniques, respectively. Image qualities of 3D ZTE and 4D ZTE at end-expiration were compared through objective and subjective assessments. The quality of end-expiratory images of 3D ZTE and 4D ZTE of the two groups with different lung functions was also compared. RESULTS Images were successfully acquired in all patients without any adverse events. Signal-to-noise ratios (SNRs) of lung parenchyma and thoracic structures were significantly (all p < 0.001) higher in 4D ZTE. Contrast-to-noise ratios (CNRs) of peripheral bronchi, peripheral pulmonary vessels, and nodules or masses were significantly (all p < 0.001) higher in 4D ZTE. The subjective image quality assessed by two independent radiologists showed that intrapulmonary structures, noise and artifacts, and overall acceptability were superior in 4D ZTE (all p < 0.001). Image qualities of groups with normal and low lung functions differed significantly (all p < 0.05) in 3D ZTE, but not in 4D ZTE. The mean acquisition time was 136 s (127-143 s) in 3D ZTE and 325 s (308-352 s) in 4D ZTE. CONCLUSIONS Respiratory motion-resolved 4D ZTE lung imaging was feasible as part of routine chest MRI. The 4D ZTE provides motion-robust lung parenchymal images with better SNR and CNR than the 3D ZTE, regardless of patients' lung function. KEY POINTS • ZTE MRI captures rapidly decaying transverse magnetization in the lung parenchyma. • 4D ZTE provides motion-robust lung parenchymal images with better SNR and CNR compared with 3D ZTE. • Compared with 3D ZTE, the image quality of 4D ZTE lung MRI was affected less by patients' lung function and respiratory performance.
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Affiliation(s)
- Kyungsoo Bae
- Department of Radiology, Institute of Health Sciences, School of Medicine, Gyeongsang National University, Jinju, South Korea.,Department of Radiology, Gyeongsang National University Changwon Hospital, 555 Samjeongja-dong, Seongsan-gu, Changwon, South Korea
| | - Kyung Nyeo Jeon
- Department of Radiology, Institute of Health Sciences, School of Medicine, Gyeongsang National University, Jinju, South Korea. .,Department of Radiology, Gyeongsang National University Changwon Hospital, 555 Samjeongja-dong, Seongsan-gu, Changwon, South Korea.
| | | | - Joon Sung Lee
- General Electric (GE) Healthcare Korea, Seoul, South Korea
| | - Sung Eun Park
- Department of Radiology, Institute of Health Sciences, School of Medicine, Gyeongsang National University, Jinju, South Korea.,Department of Radiology, Gyeongsang National University Changwon Hospital, 555 Samjeongja-dong, Seongsan-gu, Changwon, South Korea
| | - Ho Cheol Kim
- Department of Internal Medicine, School of Medicine, Gyeongsang National University, Jinju, South Korea
| | - Anne Menini
- Applied Science Lab, GE Healthcare, Menlo Park, CA, USA
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Weiger M, Pruessmann KP. Short-T 2 MRI: Principles and recent advances. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2019; 114-115:237-270. [PMID: 31779882 DOI: 10.1016/j.pnmrs.2019.07.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 07/14/2019] [Accepted: 07/26/2019] [Indexed: 06/10/2023]
Abstract
Among current modalities of biomedical and diagnostic imaging, MRI stands out by virtue of its versatile contrast obtained without ionizing radiation. However, in various cases, e.g., water protons in tissues such as bone, tendon, and lung, MRI performance is limited by the rapid decay of resonance signals associated with short transverse relaxation times T2 or T2*. Efforts to address this shortcoming have led to a variety of specialized short-T2 techniques. Recent progress in this field expands the choice of methods and prompts fresh considerations with regard to instrumentation, data acquisition, and signal processing. In this review, the current status of short-T2 MRI is surveyed. In an attempt to structure the growing range of techniques, the presentation highlights overarching concepts and basic methodological options. The most frequently used approaches are described in detail, including acquisition strategies, image reconstruction, hardware requirements, means of introducing contrast, sources of artifacts, limitations, and applications.
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Affiliation(s)
- Markus Weiger
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland.
| | - Klaas P Pruessmann
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
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Rettenmeier C, Stenger VA. Radiofrequency phase encoded half-pulses in simultaneous multislice ultrashort echo time imaging. Magn Reson Med 2019; 81:3720-3733. [PMID: 30756426 DOI: 10.1002/mrm.27693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Revised: 01/23/2019] [Accepted: 01/24/2019] [Indexed: 11/06/2022]
Abstract
PURPOSE To describe a simultaneous multislice (SMS) ultrashort echo time (UTE) imaging method using radiofrequency phase encoded half-pulses in combination with power independent of number of slices (PINS) inversion recovery (IR) pulses to generate multiple-slice images with short T2 * contrasts in less than 3 min with close to an eightfold acceleration compared with a standard 2D approach. THEORY AND METHODS Radiofrequency phase encoding is applied in an SMS (NSMS = 4) excitation scheme using "sinc" half-pulses. With the use of coil sensitivity encoding (SENSE) and controlled aliasing in parallel imaging (CAIPI) in combination with a gradient echo 2D spiral readout trajectory and IR PINS pulses for contrast enhancement a fast UTE sequence is developed. Images are obtained using a model-based reconstruction method. Sequence details and performance tests on phantoms as well as the heads of healthy volunteers at 3T are presented. RESULTS An SMS UTE sequence with an undersampling factor of 4 is developed using radiofrequency phase encoded half-pulses and PINS IR pulses which enables the acquisition of 8 slices at 0.862 mm2 resolution in less than 3-min scan time. UTE images of the head are obtained showing highlighted signal of cortical bone. Image quality and T2 contrast are comparable to the one obtained by corresponding single slice acquisitions with only minor deviations. CONCLUSIONS The method combining radiofrequency phase encoded SMS half-pulses and PINS IR pulses presents a suitable approach to SMS UTE imaging. The usage of coil sensitivity information and increased sampling density by means of interleaved slice group acquisitions allows to reduce the total scan time by a factor close to 8.
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Affiliation(s)
- Christoph Rettenmeier
- Department of Medicine, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii
| | - V Andrew Stenger
- Department of Medicine, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii
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Chandra Shekar S, Hallinan DT, Taylor DM, Chekmenev EY. Limits of Spatial Resolution of Phase Encoding Dimensions in MRI of Metals. J Phys Chem Lett 2019; 10:375-379. [PMID: 30729789 DOI: 10.1021/acs.jpclett.8b03758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Affiliation(s)
- S Chandra Shekar
- Department of Chemical and Biomedical Engineering , Florida A&M University-Florida State University College of Engineering , Tallahassee , Florida 32310 , United States
- Department of Biomedical and Health Informatics , The Children's Hospital of Philadelphia , Philadelphia , Pennsylvania 19041 , United States
| | - Daniel T Hallinan
- Department of Chemical and Biomedical Engineering , Florida A&M University-Florida State University College of Engineering , Tallahassee , Florida 32310 , United States
- Aero-propulsion, Mechatronics and Energy Center , Florida State University , Tallahassee , Florida 32310 , United States
- The National High Magnetic Field Laboratory , Florida State University , Tallahassee , Florida 32310 , United States
| | - Deanne M Taylor
- Department of Biomedical and Health Informatics , The Children's Hospital of Philadelphia , Philadelphia , Pennsylvania 19041 , United States
- Department of Pediatrics, Perelman School of Medicine , University of Pennsylvania , Philadelphia , Pennsylvania 19104 , United States
| | - Eduard Y Chekmenev
- Department of Chemistry, Karmanos Cancer Institute (KCI) and Integrative Biosciences (Ibio) , Wayne State University , Detroit , Michigan 48202 , United States
- Russian Academy of Sciences , Leninskiy Prospekt 14 , Moscow 119991 , Russia
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In vivo MRI with Concurrent Excitation and Acquisition using Automated Active Analog Cancellation. Sci Rep 2018; 8:10631. [PMID: 30006628 PMCID: PMC6045667 DOI: 10.1038/s41598-018-28894-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Accepted: 06/27/2018] [Indexed: 01/28/2023] Open
Abstract
Magnetic resonance imaging (MRI) provides excellent cross-sectional images of the soft tissues in patients. Unfortunately, MRI is intrinsically slow, it exposes patients to severe acoustic noise levels, and is limited in the visualization of certain tissues such as bone. These limitations are partly caused by the timing structure of the MRI exam which first generates the MR signal by a strong radio-frequency excitation and later acquires the weak MRI signal. Concurrent excitation and acquisition (CEA) can overcome these limitations, but is extremely challenging due to the huge intensity difference between transmit and receive signal (up to 100 dB). To suppress the strong transmit signals during signal reception, a fully automated analog cancellation unit was designed. On a 3 Tesla clinical MRI system we achieved an on-resonance analog isolation of 90 dB between the transmit and receive path, so that CEA images of the head and the extremities could be acquired with an acquisition efficiency of higher than 90% at sound pressure levels close to background noise. CEA with analog cancellation might provide new opportunities for MRI in tissues with very short T2 relaxation times, and it offers a silent and time-efficient MRI acquisition.
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Ring HL, Zhang J, Klein ND, Eberly LE, Haynes CL, Garwood M. Establishing the overlap of IONP quantification with echo and echoless MR relaxation mapping. Magn Reson Med 2017; 79:1420-1428. [PMID: 28653344 DOI: 10.1002/mrm.26800] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2017] [Revised: 05/08/2017] [Accepted: 05/27/2017] [Indexed: 12/19/2022]
Abstract
PURPOSE Iron-oxide nanoparticles (IONPs) have shown tremendous utility for enhancing image contrast and delivering targeted therapies. Quantification of IONPs has been demonstrated at low concentrations with gradient echo (GRE) and spin echo (SE), and at high concentrations with echoless sequences such as swept imaging with Fourier transform (SWIFT). This work examines the overlap of IONP quantification with GRE, SE, and SWIFT. METHODS The limit of quantification of GRE, SE, inversion-recovery GRE, and SWIFT sequences was assessed using IONPs at a concentration range of 0.02 to 89.29 mM suspended in 1% agarose. Empirically derived limits of quantification were compared with International Union of Pure and Applied Chemistry definitions. Both commercial and experimental IONPs were used. RESULTS All three IONPs assessed demonstrated an overlap of concentration quantification with GRE, SE, and SWIFT sequences. The largest dynamic range observed was 0.004 to 35.7 mM with Feraheme. CONCLUSIONS The metrics established allow upper and lower quantitative limitations to be estimated given the relaxivity characteristics of the IONP and the concentration range of the material to be assessed. The methods outlined in this paper are applicable to any pulse sequence, IONP formulation, and field strength. Magn Reson Med 79:1420-1428, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Hattie L Ring
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, Minnesota, USA.,Department of Chemistry, University of Minnesota, Minneapolis, Minnesota, USA
| | - Jinjin Zhang
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Nathan D Klein
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota, USA
| | - Lynn E Eberly
- Division of Biostatistics, University of Minnesota, Minneapolis, Minnesota, USA
| | - Christy L Haynes
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota, USA
| | - Michael Garwood
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, Minnesota, USA
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Tahayori B, Johnston LA, Layton KJ, Farrell PM, Mareels IMY. Solving the Bloch equation with periodic excitation using harmonic balancing: application to Rabi modulated excitation. IEEE TRANSACTIONS ON MEDICAL IMAGING 2015; 34:2118-2130. [PMID: 25879910 DOI: 10.1109/tmi.2015.2423313] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
In waveform design for magnetic resonance applications, periodic continuous-wave excitation offers potential advantages that remain largely unexplored because of a lack of understanding of the Bloch equation with periodic continuous-wave excitations. Using harmonic balancing techniques the steady state solutions of the Bloch equation with periodic excitation can be effectively solved. Moreover, the convergence speed of the proposed series approximation is such that a few terms in the series expansion suffice to obtain a very accurate description of the steady state solution. The accuracy of the proposed analytic approximate series solution is verified using both a simulation study as well as experimental data derived from a spherical phantom with doped water under continuous-wave excitation. Typically a five term series suffices to achieve a relative error of less than one percent, allowing for a very effective and efficient analytical design process. The opportunities for Rabi frequency modulated continuous-wave form excitation are then explored, based on a comparison with steady state free precession pulse sequences.
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Active decoupling of RF coils using a transmit array system. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2015; 28:565-76. [DOI: 10.1007/s10334-015-0497-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Revised: 07/16/2015] [Accepted: 07/17/2015] [Indexed: 10/23/2022]
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14
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Kwon HJ, Shim WH, Cho G, Cho HJ, Jung HS, Lee CK, Lee YS, Baek JH, Kim EJ, Suh JY, Sung YS, Woo DC, Kim YR, Kim JK. Simultaneous evaluation of vascular morphology, blood volume and transvascular permeability using SPION-based, dual-contrast MRI: imaging optimization and feasibility test. NMR IN BIOMEDICINE 2015; 28:624-632. [PMID: 25865029 DOI: 10.1002/nbm.3293] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Revised: 03/03/2015] [Accepted: 03/04/2015] [Indexed: 06/04/2023]
Abstract
Exploiting ultrashort-T(E) (UTE) MRI, T1-weighted positive contrast can be obtained from superparamagnetic iron oxide nanoparticles (SPIONs), which are widely used as a robust T2-weighted, negative contrast agent on conventional MR images. Our study was designed (a) to optimize the dual-contrast MRI method using SPIONs and (b) to validate the feasibility of simultaneously evaluating the vascular morphology, blood volume and transvascular permeability using the dual-contrast effect of SPIONs. All studies were conducted using 3 T MRI. According to numerical simulation, 0.15 mM was the optimal blood SPION concentration for visualizing the positive contrast effect using UTE MRI (T(E) = 0.09 ms), and a flip angle of 40° could provide sufficient SPION-induced enhancement and acceptable measurement noise for UTE MR angiography. A pharmacokinetic study showed that this concentration can be steadily maintained from 30 to 360 min after the injection of 29 mg/kg of SPIONs. An in vivo study using these settings displayed image quality and CNR of SPION-enhanced UTE MR angiography (image quality score 3.5; CNR 146) comparable to those of the conventional, Gd-enhanced method (image quality score 3.8; CNR 148) (p > 0.05). Using dual-contrast MR images obtained from SPION-enhanced UTE and conventional spin- and gradient-echo methods, the transvascular permeability (water exchange index 1.76-1.77), cerebral blood volume (2.58-2.60%) and vessel caliber index (3.06-3.10) could be consistently quantified (coefficient of variation less than 9.6%; Bland-Altman 95% limits of agreement 0.886-1.111) and were similar to the literature values. Therefore, using the optimized setting of combined SPION-based MRI techniques, the vascular morphology, blood volume and transvascular permeability can be comprehensively evaluated during a single session of MR examination.
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Affiliation(s)
- Heon-Ju Kwon
- Department of Radiology, Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Asan Institute for Life Sciences, Seoul, South Korea
- Department of Radiology, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, South Korea
| | - Woo Hyun Shim
- Department of Radiology, Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Asan Institute for Life Sciences, Seoul, South Korea
| | - Gyunggoo Cho
- Division of Magnetic Resonance, Korea Basic Science Institute, Cheongwon, Chungbuk, South Korea
| | - Hyung Joon Cho
- Ulsan National Institute of Science and Technology, Ulsan, South Korea
| | - Hoe Su Jung
- Ulsan National Institute of Science and Technology, Ulsan, South Korea
| | - Chang Kyung Lee
- Department of Radiology, Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Asan Institute for Life Sciences, Seoul, South Korea
- Division of Magnetic Resonance, Korea Basic Science Institute, Cheongwon, Chungbuk, South Korea
| | - Yong Seok Lee
- Department of Radiology, Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Asan Institute for Life Sciences, Seoul, South Korea
- Division of Magnetic Resonance, Korea Basic Science Institute, Cheongwon, Chungbuk, South Korea
| | - Jin Hee Baek
- Department of Radiology, Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Asan Institute for Life Sciences, Seoul, South Korea
- Division of Magnetic Resonance, Korea Basic Science Institute, Cheongwon, Chungbuk, South Korea
| | | | - Ji-Yeon Suh
- Division of Magnetic Resonance, Korea Basic Science Institute, Cheongwon, Chungbuk, South Korea
| | - Yu Sub Sung
- Department of Radiology, Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Asan Institute for Life Sciences, Seoul, South Korea
| | - Dong-Cheol Woo
- Department of Radiology, Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Asan Institute for Life Sciences, Seoul, South Korea
| | - Young Ro Kim
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, USA
| | - Jeong Kon Kim
- Department of Radiology, Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Asan Institute for Life Sciences, Seoul, South Korea
- Division of Magnetic Resonance, Korea Basic Science Institute, Cheongwon, Chungbuk, South Korea
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15
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Romanenko K, Forsyth M, O'Dell LA. New opportunities for quantitative and time efficient 3D MRI of liquid and solid electrochemical cell components: Sectoral Fast Spin Echo and SPRITE. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2014; 248:96-104. [PMID: 25442778 DOI: 10.1016/j.jmr.2014.09.017] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Revised: 09/18/2014] [Accepted: 09/20/2014] [Indexed: 06/04/2023]
Abstract
The ability to image electrochemical processes in situ using nuclear magnetic resonance imaging (MRI) offers exciting possibilities for understanding and optimizing materials in batteries, fuel cells and supercapacitors. In these applications, however, the quality of the MRI measurement is inherently limited by the presence of conductive elements in the cell or device. To overcome related difficulties, optimal methodologies have to be employed. We show that time-efficient three dimensional (3D) imaging of liquid and solid lithium battery components can be performed by Sectoral Fast Spin Echo and Single Point Imaging with T1 Enhancement (SPRITE), respectively. The former method is based on the generalized phase encoding concept employed in clinical MRI, which we have adapted and optimized for materials science and electrochemistry applications. Hard radio frequency pulses, short echo spacing and centrically ordered sectoral phase encoding ensure accurate and time-efficient full volume imaging. Mapping of density, diffusivity and relaxation time constants in metal-containing liquid electrolytes is demonstrated. 1, 2 and 3D SPRITE approaches show strong potential for rapid high resolution (7)Li MRI of lithium electrode components.
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Affiliation(s)
- Konstantin Romanenko
- Institute for Frontier Materials, Deakin University, Waurn Ponds Campus, Geelong, Victoria 3220, Australia.
| | - Maria Forsyth
- Institute for Frontier Materials, Deakin University, Waurn Ponds Campus, Geelong, Victoria 3220, Australia
| | - Luke A O'Dell
- Institute for Frontier Materials, Deakin University, Waurn Ponds Campus, Geelong, Victoria 3220, Australia
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16
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Wang L, Tang W, Zhen Z, Chen H, Xie J, Zhao Q. Improving detection specificity of iron oxide nanoparticles (IONPs) using the SWIFT sequence with long T(2) suppression. Magn Reson Imaging 2014; 32:671-8. [PMID: 24666573 DOI: 10.1016/j.mri.2014.02.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Revised: 01/08/2014] [Accepted: 02/11/2014] [Indexed: 01/25/2023]
Abstract
In order to improve the detection specificity of iron oxide nanoparticles (IONPs) delivered to tumors, we embedded saturation pulses into the sweep imaging using Fourier transformation (SWIFT) sequence to suppress long T(2) tissues and fat. Simulation of the Bloch equation was first conducted to study behavior of the saturation pulses of various lengths under different T(2) and off-resonance conditions. MR experiments were then conducted using in vivo mouse xenografts and a phantom consisting of IONPs, vegetable oil, and explanted tumor specimen, without and with long T(2) suppression under a 7T magnetic field. For the in vivo study, arginine-glycine-aspartate (RGD) coated 10nm IONPs (RGD-IONPs) were delivered to tumors implanted in nude mice through both intra-tumor and intravenous injections. Histological studies confirmed that RGD-IONPs efficiently homed to tumors through RGD-integrin interaction. Compared to conventional SWIFT, the proposed method resulted in sufficient suppression on long T(2) species but less influence on short T(2) species. For both the in vivo and ex vivo studies, significantly improved contrast-to-noise ratio (CNR) was achieved between the IONPs and the long T(2) species.
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Affiliation(s)
- Luning Wang
- Department of Physics and Astronomy, University of Georgia, Athens, US; BioImaging Research Center (BIRC), University of Georgia, Athens, US
| | - Wei Tang
- Department of Chemistry, University of Georgia, Athens, US
| | - Zipeng Zhen
- Department of Chemistry, University of Georgia, Athens, US
| | - Hongming Chen
- Department of Chemistry, University of Georgia, Athens, US
| | - Jin Xie
- Department of Chemistry, University of Georgia, Athens, US; BioImaging Research Center (BIRC), University of Georgia, Athens, US
| | - Qun Zhao
- Department of Physics and Astronomy, University of Georgia, Athens, US; BioImaging Research Center (BIRC), University of Georgia, Athens, US.
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