1
|
Davids M, Vendramini L, Klein V, Ferris N, Guerin B, Wald LL. Experimental validation of a PNS-optimized whole-body gradient coil. Magn Reson Med 2024; 92:1788-1803. [PMID: 38767407 PMCID: PMC11262990 DOI: 10.1002/mrm.30157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2023] [Revised: 03/19/2024] [Accepted: 04/28/2024] [Indexed: 05/22/2024]
Abstract
PURPOSE Peripheral nerve stimulation (PNS) limits the usability of state-of-the-art whole-body and head-only MRI gradient coils. We used detailed electromagnetic and neurodynamic modeling to set an explicit PNS constraint during the design of a whole-body gradient coil and constructed it to compare the predicted and experimentally measured PNS thresholds to those of a matched design without PNS constraints. METHODS We designed, constructed, and tested two actively shielded whole-body Y-axis gradient coil winding patterns: YG1 is a conventional symmetric design without PNS-optimization, whereas YG2's design used an additional constraint on the allowable PNS threshold in the head-imaging landmark, yielding an asymmetric winding pattern. We measured PNS thresholds in 18 healthy subjects at five landmark positions (head, cardiac, abdominal, pelvic, and knee). RESULTS The PNS-optimized design YG2 achieved 46% higher average experimental thresholds for a head-imaging landmark than YG1 while incurring a 15% inductance penalty. For cardiac, pelvic, and knee imaging landmarks, the PNS thresholds increased between +22% and +35%. For abdominal imaging, PNS thresholds did not change significantly between YG1 and YG2 (-3.6%). The agreement between predicted and experimental PNS thresholds was within 11.4% normalized root mean square error for both coils and all landmarks. The PNS model also produced plausible predictions of the stimulation sites when compared to the sites of perception reported by the subjects. CONCLUSION The PNS-optimization improved the PNS thresholds for the target scan landmark as well as most other studied landmarks, potentially yielding a significant improvement in image encoding performance that can be safely used in humans.
Collapse
Affiliation(s)
- Mathias Davids
- Martinos Center for Biomedical Imaging, Charlestown, MA, United States
- Harvard Medical School, Boston, MA, United States
| | - Livia Vendramini
- Martinos Center for Biomedical Imaging, Charlestown, MA, United States
| | - Valerie Klein
- Martinos Center for Biomedical Imaging, Charlestown, MA, United States
- Harvard Medical School, Boston, MA, United States
| | - Natalie Ferris
- Harvard Graduate Program in Biophysics, Harvard University, Cambridge, MA, United States
- Harvard-MIT Division of Health Sciences and Technology, Boston, MA, United States
| | - Bastien Guerin
- Martinos Center for Biomedical Imaging, Charlestown, MA, United States
- Harvard Medical School, Boston, MA, United States
| | - Lawrence L. Wald
- Martinos Center for Biomedical Imaging, Charlestown, MA, United States
- Harvard Medical School, Boston, MA, United States
- Harvard-MIT Division of Health Sciences and Technology, Boston, MA, United States
| |
Collapse
|
2
|
Lee SK, Hua Y. Theory and mitigation of motional eddy current in high-field eddy current shielding. JOURNAL OF APPLIED PHYSICS 2024; 136:024504. [PMID: 39006886 PMCID: PMC11246172 DOI: 10.1063/5.0210709] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/26/2024] [Accepted: 06/20/2024] [Indexed: 07/16/2024]
Abstract
Eddy current shielding by a Faraday cage is an effective way to shield alternating-current magnetic fields in scientific instrumentation. In a strong static magnetic field, however, the eddy current in the conductive shield is subject to the Lorentz force, which causes the shield to vibrate. In addition to mechanical issues (e.g., acoustic noise), such vibration induces motional eddy current in the shield that can dominate the original, electromagnetic eddy current to undermine the conductor's shielding capability. In this work, we investigate a method to control motional eddy current by making cut-out patterns in the conductor that follow the electromagnetic eddy current image. This effectively limits the surface current of the plate to a single mode and prevents the proliferation of uncontrolled motion-induced surface currents that disrupts eddy current shielding. After developing a comprehensive theory of magneto-mechanical interaction in a conductive plate, the proposed method was tested on a flat-geometry testbed experiment inside a 3 T magnetic resonance imaging (MRI) magnet. It was found that the magnetic field generated by the motional eddy current was much more localized in space and frequency for a patterned-copper shield compared to a solid copper. The magnetic field of the patterned shield could be accurately predicted from the impedance measurement in the magnet. Implications of our results for improved shielding of gradient fields in high-field MRI are discussed.
Collapse
Affiliation(s)
- Seung-Kyun Lee
- GE HealthCare Technology & Innovation Center, Niskayuna, New York 12309, USA
| | - Yihe Hua
- GE HealthCare Technology & Innovation Center, Niskayuna, New York 12309, USA
| |
Collapse
|
3
|
Stirnberg R, Deistung A, Reichenbach JR, Breteler MMB, Stöcker T. Rapid submillimeter QSM and R 2* mapping using interleaved multishot 3D-EPI at 7 and 3 Tesla. Magn Reson Med 2024. [PMID: 38988040 DOI: 10.1002/mrm.30216] [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: 12/28/2023] [Revised: 06/05/2024] [Accepted: 06/24/2024] [Indexed: 07/12/2024]
Abstract
PURPOSE To explore the high signal-to-noise ratio (SNR) efficiency of interleaved multishot 3D-EPI with standard image reconstruction for fast and robust high-resolution whole-brain quantitative susceptibility (QSM) andR 2 ∗ $$ {R}_2^{\ast } $$ mapping at 7 and 3T. METHODS Single- and multi-TE segmented 3D-EPI is combined with conventional CAIPIRINHA undersampling for up to 72-fold effective gradient echo (GRE) imaging acceleration. Across multiple averages, scan parameters are varied (e.g., dual-polarity frequency-encoding) to additionally correct forB 0 $$ {\mathrm{B}}_0 $$ -induced artifacts, geometric distortions and motion retrospectively. A comparison to established GRE protocols is made. Resolutions range from 1.4 mm isotropic (1 multi-TE average in 36 s) up to 0.4 mm isotropic (2 single-TE averages in approximately 6 min) with whole-head coverage. RESULTS Only 1-4 averages are needed for sufficient SNR with 3D-EPI, depending on resolution and field strength. Fast scanning and small voxels together with retrospective corrections result in substantially reduced image artifacts, which improves susceptibility andR 2 ∗ $$ {R}_2^{\ast } $$ mapping. Additionally, much finer details are obtained in susceptibility-weighted image projections through significantly reduced partial voluming. CONCLUSION Using interleaved multishot 3D-EPI, single-TE and multi-TE data can readily be acquired 10 times faster than with conventional, accelerated GRE imaging. Even 0.4 mm isotropic whole-head QSM within 6 min becomes feasible at 7T. At 3T, motion-robust 0.8 mm isotropic whole-brain QSM andR 2 ∗ $$ {R}_2^{\ast } $$ mapping with no apparent distortion in less than 7 min becomes clinically feasible. Stronger gradient systems may allow for even higher effective acceleration rates through larger EPI factors while maintaining optimal contrast.
Collapse
Affiliation(s)
- Rüdiger Stirnberg
- MR Physics, German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Andreas Deistung
- Clinic and Outpatient Clinic for Radiology, University Hospital Halle (Saale), University Medicine Halle, Halle (Saale), Germany
| | - Jürgen R Reichenbach
- Medical Physics Group, Institute of Diagnostic and Interventional Radiology, Jena University Hospital, Jena, Germany
| | - Monique M B Breteler
- Population Health Sciences, German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
- Faculty of Medicine, Institute for Medical Biometry, Informatics and Epidemiology (IMBIE), University of Bonn, Bonn, Germany
| | - Tony Stöcker
- MR Physics, German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
- Department of Physics and Astronomy, University of Bonn, Bonn, Germany
| |
Collapse
|
4
|
Herthum H, Hetzer S. Tensor denoising of quantitative multi-parameter mapping. Magn Reson Med 2024; 92:145-157. [PMID: 38368616 DOI: 10.1002/mrm.30050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 01/12/2024] [Accepted: 01/25/2024] [Indexed: 02/20/2024]
Abstract
PURPOSE Quantitative multi-parameter mapping (MPM) provides maps of physical quantities representing physiologically meaningful tissue characteristics, which allows to investigate microstructure-function relationships reflecting normal or pathologic processes in the brain. However, the achievable spatial resolution and stability of MPM for basic research or clinical applications is severely constrained by SNR limits of the MR acquisition process, resulting in relatively long acquisition times. To increase SNR, we denoise MPM acquisitions using principal component analysis along tensors exploiting the Marchenko-Pastur law (tMPPCA). METHODS tMPPCA denoising was applied to three sets of MPM raw data before the quantification of maps of proton density, magnetization transfer saturation, R1, and R2*. The regional SNR gain for high-resolution MPM was investigated as well as reproducibility gains for clinically optimized protocols with moderate and high acceleration factors at different image resolutions. RESULTS Substantial noise reduction in raw data was achieved, resulting in reduced noise for quantitative mapping up to sixfold without introducing bias of mean values (below 1%). Scan-rescan fluctuations were reduced up to threefold. Denoising allowed to decrease the voxel volume fourfold at the same scan time or reduce the scan time twofold at same voxel volume without loss of sensitivity. CONCLUSIONS tMPPCA denoising can (a) improve of fine spatial and temporal patterns, (b) considerably reduce scan time for clinical applications, or (c) increase resolution to potentially push cutting-edge MPM protocols from the upper to the lower limit of the mesoscopic scale.
Collapse
Affiliation(s)
- Helge Herthum
- Berlin Center for Advanced Neuroimaging, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
- Bernstein Center for Computational Neuroscience, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Stefan Hetzer
- Berlin Center for Advanced Neuroimaging, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
- Bernstein Center for Computational Neuroscience, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| |
Collapse
|
5
|
Condron P, Cornfeld DM, Scadeng M, Melzer TR, Newburn G, Bydder M, Kwon EE, McGeown JP, Handsfield GG, Emsden T, Tayebi M, Holdsworth SJ, Bydder GM. Ultra-High Contrast MRI: The Whiteout Sign Shown with Divided Subtracted Inversion Recovery (dSIR) Sequences in Post-Insult Leukoencephalopathy Syndromes (PILS). Tomography 2024; 10:983-1013. [PMID: 39058046 DOI: 10.3390/tomography10070074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2024] [Revised: 06/17/2024] [Accepted: 06/20/2024] [Indexed: 07/28/2024] Open
Abstract
Ultra-high contrast (UHC) MRI describes forms of MRI in which little or no contrast is seen on conventional MRI images but very high contrast is seen with UHC techniques. One of these techniques uses the divided subtracted inversion recovery (dSIR) sequence, which, in modelling studies, can produce ten times the contrast of conventional inversion recovery (IR) sequences. When used in cases of mild traumatic brain injury (mTBI), the dSIR sequence frequently shows extensive abnormalities in white matter that appears normal when imaged with conventional T2-fluid-attenuated IR (T2-FLAIR) sequences. The changes are bilateral and symmetrical in white matter of the cerebral and cerebellar hemispheres. They partially spare the anterior and posterior central corpus callosum and peripheral white matter of the cerebral hemispheres and are described as the whiteout sign. In addition to mTBI, the whiteout sign has also been seen in methamphetamine use disorder and Grinker's myelinopathy (delayed post-hypoxic leukoencephalopathy) in the absence of abnormalities on T2-FLAIR images, and is a central component of post-insult leukoencephalopathy syndromes. This paper describes the concept of ultra-high contrast MRI, the whiteout sign, the theory underlying the use of dSIR sequences and post-insult leukoencephalopathy syndromes.
Collapse
Affiliation(s)
- Paul Condron
- Mātai Medical Research Institute, Tairāwhiti Gisborne 4010, New Zealand
- Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences & Centre for Brain Research, University of Auckland, Auckland 1010, New Zealand
| | - Daniel M Cornfeld
- Mātai Medical Research Institute, Tairāwhiti Gisborne 4010, New Zealand
- Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences & Centre for Brain Research, University of Auckland, Auckland 1010, New Zealand
| | - Miriam Scadeng
- Mātai Medical Research Institute, Tairāwhiti Gisborne 4010, New Zealand
- Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences & Centre for Brain Research, University of Auckland, Auckland 1010, New Zealand
| | - Tracy R Melzer
- Department of Medicine, University of Otago, Christchurch 8011, New Zealand
- New Zealand Brain Research Institute, Christchurch 8011, New Zealand
| | - Gil Newburn
- Mātai Medical Research Institute, Tairāwhiti Gisborne 4010, New Zealand
| | - Mark Bydder
- Mātai Medical Research Institute, Tairāwhiti Gisborne 4010, New Zealand
| | - Eryn E Kwon
- Mātai Medical Research Institute, Tairāwhiti Gisborne 4010, New Zealand
- Auckland Bioengineering Institute, University of Auckland, Auckland 1010, New Zealand
| | - Joshua P McGeown
- Mātai Medical Research Institute, Tairāwhiti Gisborne 4010, New Zealand
| | - Geoffrey G Handsfield
- Mātai Medical Research Institute, Tairāwhiti Gisborne 4010, New Zealand
- Auckland Bioengineering Institute, University of Auckland, Auckland 1010, New Zealand
| | - Taylor Emsden
- Mātai Medical Research Institute, Tairāwhiti Gisborne 4010, New Zealand
| | - Maryam Tayebi
- Mātai Medical Research Institute, Tairāwhiti Gisborne 4010, New Zealand
- Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences & Centre for Brain Research, University of Auckland, Auckland 1010, New Zealand
| | - Samantha J Holdsworth
- Mātai Medical Research Institute, Tairāwhiti Gisborne 4010, New Zealand
- Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences & Centre for Brain Research, University of Auckland, Auckland 1010, New Zealand
| | - Graeme M Bydder
- Mātai Medical Research Institute, Tairāwhiti Gisborne 4010, New Zealand
- Department of Radiology, University of California San Diego, San Diego, CA 92093, USA
| |
Collapse
|
6
|
Wijtenburg SA, Rowland LM, Vicentic A, Rossi AF, Brady LS, Gordon JA, Lisanby SH. NIMH perspectives on future directions in neuroimaging for mental health. Neuropsychopharmacology 2024:10.1038/s41386-024-01900-8. [PMID: 38898207 DOI: 10.1038/s41386-024-01900-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2024] [Revised: 05/31/2024] [Accepted: 06/02/2024] [Indexed: 06/21/2024]
Abstract
NIMH's mission is to transform the understanding and treatment of mental illnesses through basic and clinical research, paving the way for prevention, recovery, and cure. New imaging techniques hold great promise for improving our understanding of the pathophysiology of mental illnesses, stratifying patients for treatment selection, and developing a personalized medicine approach. Here, we highlight emerging and promising new technologies that are likely to be vital in helping NIMH accomplish its mission, the potential for utilizing multimodal approaches to study mental illness, and considerations for data analytics and data sharing.
Collapse
Affiliation(s)
- S Andrea Wijtenburg
- National Institute of Mental Health, National Institutes of Health, Rockville, MD, USA.
| | - Laura M Rowland
- National Institute of Mental Health, National Institutes of Health, Rockville, MD, USA
| | - Aleksandra Vicentic
- National Institute of Mental Health, National Institutes of Health, Rockville, MD, USA
| | - Andrew F Rossi
- National Institute of Mental Health, National Institutes of Health, Rockville, MD, USA
| | - Linda S Brady
- National Institute of Mental Health, National Institutes of Health, Rockville, MD, USA
| | - Joshua A Gordon
- National Institute of Mental Health, National Institutes of Health, Rockville, MD, USA
| | - Sarah H Lisanby
- National Institute of Mental Health, National Institutes of Health, Rockville, MD, USA
| |
Collapse
|
7
|
Waks M, Lagore RL, Auerbach E, Grant A, Sadeghi-Tarakameh A, DelaBarre L, Jungst S, Tavaf N, Lattanzi R, Giannakopoulos I, Moeller S, Wu X, Yacoub E, Vizioli L, Schmidt S, Metzger GJ, Eryaman Y, Adriany G, Uğurbil K. RF coil design strategies for improving SNR at the ultrahigh magnetic field of 10.5 Tesla. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.23.595628. [PMID: 38826245 PMCID: PMC11142186 DOI: 10.1101/2024.05.23.595628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2024]
Abstract
Purpose To develop multichannel transmit and receive arrays towards capturing the ultimate-intrinsic-SNR (uiSNR) at 10.5 Tesla (T) and to demonstrate the feasibility and potential of whole-brain, high-resolution human brain imaging at this high field strength. Methods A dual row 16-channel self-decoupled transmit (Tx) array was converted to a 16Tx/Rx transceiver using custom transmit/receive switches. A 64-channel receive-only (64Rx) array was built to fit into the 16Tx/Rx array. Electromagnetic modeling and experiments were employed to define safe operation limits of the resulting 16Tx/80Rx array and obtain FDA approval for human use. Results The 64Rx array alone captured approximately 50% of the central uiSNR at 10.5T while the identical 7T 64Rx array captured ∼76% of uiSNR at this lower field strength. The 16Tx/80Rx configuration brought the fraction of uiSNR captured at 10.5T to levels comparable to the performance of the 64Rx array at 7T. SNR data obtained at the two field strengths with these arrays displayed dependent increases over a large central region. Whole-brain high resolution T 2 * and T 1 weighted anatomical and gradient-recalled echo EPI BOLD fMRI images were obtained at 10.5T for the first time with such an advanced array, illustrating the promise of >10T fields in studying the human brain. Conclusion We demonstrated the ability to approach the uiSNR at 10.5T over the human brain with a novel, high channel count array, achieving large SNR gains over 7T, currently the most commonly employed ultrahigh field platform, and demonstrate high resolution and high contrast anatomical and functional imaging at 10.5T.
Collapse
|
8
|
Mertz L. Ultra-High to Ultra-Low: MRI Goes to Extremes. IEEE Pulse 2024; 15:9-14. [PMID: 39024065 DOI: 10.1109/mpuls.2024.3405768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/20/2024]
Abstract
Two of the hottest areas in magnetic resonance imaging (MRI) are at the extremes.
Collapse
|
9
|
Wu D, Kang L, Li H, Ba R, Cao Z, Liu Q, Tan Y, Zhang Q, Li B, Yuan J. Developing an AI-empowered head-only ultra-high-performance gradient MRI system for high spatiotemporal neuroimaging. Neuroimage 2024; 290:120553. [PMID: 38403092 DOI: 10.1016/j.neuroimage.2024.120553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 02/20/2024] [Accepted: 02/22/2024] [Indexed: 02/27/2024] Open
Abstract
Recent advances in neuroscience requires high-resolution MRI to decipher the structural and functional details of the brain. Developing a high-performance gradient system is an ongoing effort in the field to facilitate high spatial and temporal encoding. Here, we proposed a head-only gradient system NeuroFrontier, dedicated for neuroimaging with an ultra-high gradient strength of 650 mT/m and 600 T/m/s. The proposed system features in 1) ultra-high power of 7MW achieved by running two gradient power amplifiers using a novel paralleling method; 2) a force/torque balanced gradient coil design with a two-step mechanical structure that allows high-efficiency and flexible optimization of the peripheral nerve stimulation; 3) a high-density integrated RF system that is miniaturized and customized for the head-only system; 4) an AI-empowered compressed sensing technique that enables ultra-fast acquisition of high-resolution images and AI-based acceleration in q-t space for diffusion MRI (dMRI); and 5) a prospective head motion correction technique that effectively corrects motion artifacts in real-time with 3D optical tracking. We demonstrated the potential advantages of the proposed system in imaging resolution, speed, and signal-to-noise ratio for 3D structural MRI (sMRI), functional MRI (fMRI) and dMRI in neuroscience applications of submillimeter layer-specific fMRI and dMRI. We also illustrated the unique strength of this system for dMRI-based microstructural mapping, e.g., enhanced lesion contrast at short diffusion-times or high b-values, and improved estimation accuracy for cellular microstructures using diffusion-time-dependent dMRI or for neurite microstructures using q-space approaches.
Collapse
Affiliation(s)
- Dan Wu
- Department of Biomedical Engineering, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, China; Innovation Center for Smart Medical Technologies & Devices, Binjiang Institute of Zhejiang University, Hangzhou, China.
| | - Liyi Kang
- Department of Biomedical Engineering, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, China; Innovation Center for Smart Medical Technologies & Devices, Binjiang Institute of Zhejiang University, Hangzhou, China
| | - Haotian Li
- Department of Biomedical Engineering, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, China
| | - Ruicheng Ba
- Department of Biomedical Engineering, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, China
| | - Zuozhen Cao
- Department of Biomedical Engineering, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, China
| | - Qian Liu
- United Imaging Healthcare Co., Ltd, Shanghai, China
| | - Yingchao Tan
- United Imaging Healthcare Co., Ltd, Shanghai, China
| | - Qinwei Zhang
- Beijing United Imaging Research Institute of Intelligent Imaging, Beijing, China
| | - Bo Li
- United Imaging Healthcare Co., Ltd, Shanghai, China
| | - Jianmin Yuan
- United Imaging Healthcare Co., Ltd, Shanghai, China
| |
Collapse
|
10
|
Dong Z, Reese TG, Lee HH, Huang SY, Polimeni JR, Wald LL, Wang F. Romer-EPTI: rotating-view motion-robust super-resolution EPTI for SNR-efficient distortion-free in-vivo mesoscale dMRI and microstructure imaging. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.26.577343. [PMID: 38352481 PMCID: PMC10862730 DOI: 10.1101/2024.01.26.577343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/19/2024]
Abstract
Purpose To overcome the major challenges in dMRI acquisition, including low SNR, distortion/blurring, and motion vulnerability. Methods A novel Romer-EPTI technique is developed to provide distortion-free dMRI with significant SNR gain, high motion-robustness, sharp spatial resolution, and simultaneous multi-TE imaging. It introduces a ROtating-view Motion-robust supEr-Resolution technique (Romer) combined with a distortion/blurring-free EPTI encoding. Romer enhances SNR by a simultaneous multi-thick-slice acquisition with rotating-view encoding, while providing high motion-robustness through a motion-aware super-resolution reconstruction, which also incorporates slice-profile and real-value diffusion, to resolve high-isotropic-resolution volumes. The in-plane encoding is performed using distortion/blurring-free EPTI, which further improves effective spatial resolution and motion robustness by preventing not only T2/T2*-blurring but also additional blurring resulting from combining encoded volumes with inconsistent geometries caused by dynamic distortions. Self-navigation was incorporated to enable efficient phase correction. Additional developments include strategies to address slab-boundary artifacts, achieve minimal TE for SNR gain at 7T, and achieve high robustness to strong phase variations at high b-values. Results Using Romer-EPTI, we demonstrate distortion-free whole-brain mesoscale in-vivo dMRI at both 3T (500-μm-iso) and 7T (485-μm-iso) for the first time, with high SNR efficiency (e.g., 25 × ), and high image quality free from distortion and slab-boundary artifacts with minimal blurring. Motion experiments demonstrate Romer-EPTI's high motion-robustness and ability to recover sharp images in the presence of motion. Romer-EPTI also demonstrates significant SNR gain and robustness in high b-value (b=5000s/mm2) and time-dependent dMRI. Conclusion Romer-EPTI significantly improves SNR, motion-robustness, and image quality, providing a highly efficient acquisition for high-resolution dMRI and microstructure imaging.
Collapse
Affiliation(s)
- Zijing Dong
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, USA
- Department of Radiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Timothy G. Reese
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, USA
- Department of Radiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Hong-Hsi Lee
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, USA
- Department of Radiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Susie Y. Huang
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, USA
- Department of Radiology, Harvard Medical School, Boston, Massachusetts, USA
- Harvard-MIT Health Sciences and Technology, MIT, Cambridge, Massachusetts, USA
| | - Jonathan R. Polimeni
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, USA
- Department of Radiology, Harvard Medical School, Boston, Massachusetts, USA
- Harvard-MIT Health Sciences and Technology, MIT, Cambridge, Massachusetts, USA
| | - Lawrence L. Wald
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, USA
- Department of Radiology, Harvard Medical School, Boston, Massachusetts, USA
- Harvard-MIT Health Sciences and Technology, MIT, Cambridge, Massachusetts, USA
| | - Fuyixue Wang
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, USA
- Department of Radiology, Harvard Medical School, Boston, Massachusetts, USA
| |
Collapse
|
11
|
Boulant N, Le Ster C, Amadon A, Aubert G, Beckett A, Belorgey J, Bonnelye C, Bosch D, Brunner DO, Dilasser G, Dubois O, Ehses P, Feinberg D, Feizollah S, Gras V, Gross S, Guihard Q, Lannou H, Le Bihan D, Mauconduit F, Molinié F, Nunio F, Pruessmann K, Quettier L, Scheffler K, Stöcker T, Tardif C, Ugurbil K, Vignaud A, Vu A, Wu X. The possible influence of third-order shim coils on gradient-magnet interactions: an inter-field and inter-site study. MAGMA (NEW YORK, N.Y.) 2024; 37:169-183. [PMID: 38197908 PMCID: PMC10995016 DOI: 10.1007/s10334-023-01138-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 11/28/2023] [Accepted: 11/30/2023] [Indexed: 01/11/2024]
Abstract
OBJECTIVE To assess the possible influence of third-order shim coils on the behavior of the gradient field and in gradient-magnet interactions at 7 T and above. MATERIALS AND METHODS Gradient impulse response function measurements were performed at 5 sites spanning field strengths from 7 to 11.7 T, all of them sharing the same exact whole-body gradient coil design. Mechanical fixation and boundary conditions of the gradient coil were altered in several ways at one site to study the impact of mechanical coupling with the magnet on the field perturbations. Vibrations, power deposition in the He bath, and field dynamics were characterized at 11.7 T with the third-order shim coils connected and disconnected inside the Faraday cage. RESULTS For the same whole-body gradient coil design, all measurements differed greatly based on the third-order shim coil configuration (connected or not). Vibrations and gradient transfer function peaks could be affected by a factor of 2 or more, depending on the resonances. Disconnecting the third-order shim coils at 11.7 T also suppressed almost completely power deposition peaks at some frequencies. DISCUSSION Third-order shim coil configurations can have major impact in gradient-magnet interactions with consequences on potential hardware damage, magnet heating, and image quality going beyond EPI acquisitions.
Collapse
Affiliation(s)
- Nicolas Boulant
- CEA, CNRS, BAOBAB, NeuroSpin, University Paris-Saclay, 91191, Gif Sur Yvette Cedex, France.
| | - Caroline Le Ster
- CEA, CNRS, BAOBAB, NeuroSpin, University Paris-Saclay, 91191, Gif Sur Yvette Cedex, France
| | - Alexis Amadon
- CEA, CNRS, BAOBAB, NeuroSpin, University Paris-Saclay, 91191, Gif Sur Yvette Cedex, France
| | - Guy Aubert
- CEA, Irfu, DACM, University Paris-Saclay, Gif Sur Yvette, France
| | - Alexander Beckett
- Brain Imaging Center and Helen Wills Neuroscience Institute, University of California, Berkeley, CA, USA
- Advanced MRI Technologies, Sebastopol, CA, USA
| | - Jean Belorgey
- CEA, Irfu, DIS, University Paris-Saclay, Gif Sur Yvette, France
| | - Cédric Bonnelye
- CEA, CNRS, BAOBAB, NeuroSpin, University Paris-Saclay, 91191, Gif Sur Yvette Cedex, France
| | - Dario Bosch
- Department for Biomedical Magnetic Resonance, University of Tübingen, Tübingen, Germany
- High-Field MR Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany
| | | | | | - Olivier Dubois
- CEA, Irfu, DIS, University Paris-Saclay, Gif Sur Yvette, France
| | | | - David Feinberg
- Brain Imaging Center and Helen Wills Neuroscience Institute, University of California, Berkeley, CA, USA
- Advanced MRI Technologies, Sebastopol, CA, USA
| | - Sajjad Feizollah
- Montreal Neurological Institute-Hospital, McGill University, Montreal, QC, Canada
| | - Vincent Gras
- CEA, CNRS, BAOBAB, NeuroSpin, University Paris-Saclay, 91191, Gif Sur Yvette Cedex, France
| | | | - Quentin Guihard
- CEA, Irfu, DIS, University Paris-Saclay, Gif Sur Yvette, France
| | - Hervé Lannou
- CEA, Irfu, DACM, University Paris-Saclay, Gif Sur Yvette, France
| | - Denis Le Bihan
- CEA, CNRS, BAOBAB, NeuroSpin, University Paris-Saclay, 91191, Gif Sur Yvette Cedex, France
| | - Franck Mauconduit
- CEA, CNRS, BAOBAB, NeuroSpin, University Paris-Saclay, 91191, Gif Sur Yvette Cedex, France
| | | | - François Nunio
- CEA, Irfu, DIS, University Paris-Saclay, Gif Sur Yvette, France
| | | | - Lionel Quettier
- CEA, Irfu, DACM, University Paris-Saclay, Gif Sur Yvette, France
| | - Klaus Scheffler
- Department for Biomedical Magnetic Resonance, University of Tübingen, Tübingen, Germany
- High-Field MR Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany
| | - Tony Stöcker
- Center for Neurogenerative Diseases, Bonn, Germany
| | - Christine Tardif
- Montreal Neurological Institute-Hospital, McGill University, Montreal, QC, Canada
| | - Kamil Ugurbil
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, USA
| | - Alexandre Vignaud
- CEA, CNRS, BAOBAB, NeuroSpin, University Paris-Saclay, 91191, Gif Sur Yvette Cedex, France
| | - An Vu
- University of California, San Francisco, CA, USA
- San Francisco VA Health Care System, San Francisco, CA, USA
| | - Xiaoping Wu
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, USA
| |
Collapse
|
12
|
Maurya SK, Schmidt R. A Metamaterial-like Structure Design Using Non-uniformly Distributed Dielectric and Conducting Strips to Boost the RF Field Distribution in 7 T MRI. SENSORS (BASEL, SWITZERLAND) 2024; 24:2250. [PMID: 38610461 PMCID: PMC11014008 DOI: 10.3390/s24072250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Revised: 03/24/2024] [Accepted: 03/28/2024] [Indexed: 04/14/2024]
Abstract
Metamaterial-based designs in ultra-high field (≥7 T) MRI have the promise of increasing the local magnetic resonance imaging (MRI) signal and potentially even the global efficiency of both the radiofrequency (RF) transmit and receive resonators. A recently proposed metamaterial-like structure-comprised of a high-permittivity dielectric material and a set of evenly distributed copper strips-indeed resulted in a local increase in RF transmission. Here, we demonstrate that non-uniform designs of this metamaterial-like structure can be used to boost the ultimate RF field distribution. A non-uniform dielectric distribution can yield longer electric dipoles, thus extending the RF transmit field coverage. A non-uniform distribution of conducting strips enables the tailoring of the local electric field hot spots, where a concave distribution resulted in lower power deposition. Simulations of the brain and calf regions using our new metamaterial-like design, which combines non-uniform distributions of both the dielectric and conducting strips, revealed a 1.4-fold increase in the RF field coverage compared to the uniform distribution, and a 1.5-2-fold increase in the transmit efficiency compared to the standard surface-coil.
Collapse
Affiliation(s)
- Santosh Kumar Maurya
- Department of Brain Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel;
- The Azrieli National Institute for Human Brain Imaging and Research, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Rita Schmidt
- Department of Brain Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel;
- The Azrieli National Institute for Human Brain Imaging and Research, Weizmann Institute of Science, Rehovot 7610001, Israel
| |
Collapse
|
13
|
Xiao L, Zhang L, Li S, Zhu Y, Yu Q, Liu Z, Qiu M, Li Y, Chen S, Zhou X. Visualization and Quantification of Drug Release by GSH-Responsive Multimodal Integrated Micelles. JACS AU 2024; 4:1194-1206. [PMID: 38559742 PMCID: PMC10976607 DOI: 10.1021/jacsau.4c00009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Revised: 02/13/2024] [Accepted: 02/14/2024] [Indexed: 04/04/2024]
Abstract
Using molecular imaging techniques to monitor biomarkers and drug release profiles simultaneously is highly advantageous for cancer diagnosis and treatment. However, achieving the accurate quantification of both biomarkers and drug release with a single imaging modality is challenging. This study presents the development of a glutathione (GSH)-responsive polymer-based micelle, PEG-SS-FCy7/PEG-SS-GEM (PSFG), which can precisely localize the tumor using bimodal imaging and prevent drug leakage. These PSFG micelles exhibit a small particle size of 106.3 ± 12.7 nm with a uniform size distribution, and the drug loading efficiency can also be easily controlled by changing the PEG-SS-FCy7 (PSF) and PEG-SS-GEM (PSG) feeding ratio. The PSFG micelles display weak fluorescence emission and minimal drug release under physiological conditions but collapse in the presence of GSH to trigger near-infrared fluorescence and the 19F magnetic resonance imaging signal, allowing for real-time monitoring of intracellular GSH levels and drug release. GSH could synergistically promote the disassembly of the micellar structure, resulting in accelerated probe and drug release of up to about 93.1% after 24 h. These prodrug micelles exhibit high in vitro and in vivo antitumor abilities with minimal side effects. The GSH-responsive drug delivery system with dual-modal imaging capability provides a promising imaging-guided chemotherapeutic platform to probe the tumor microenvironment and quantify real-time drug release profiles with minimal side effects.
Collapse
Affiliation(s)
- Long Xiao
- State
Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics,
National Center for Magnetic Resonance in Wuhan, Wuhan Institute of
Physics and Mathematics, Innovation Academy
for Precision Measurement Science and Technology, Chinese Academy
of Sciences, Wuhan 430071, P. R. China
- University
of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Lei Zhang
- State
Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics,
National Center for Magnetic Resonance in Wuhan, Wuhan Institute of
Physics and Mathematics, Innovation Academy
for Precision Measurement Science and Technology, Chinese Academy
of Sciences, Wuhan 430071, P. R. China
- University
of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Sha Li
- State
Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics,
National Center for Magnetic Resonance in Wuhan, Wuhan Institute of
Physics and Mathematics, Innovation Academy
for Precision Measurement Science and Technology, Chinese Academy
of Sciences, Wuhan 430071, P. R. China
| | - Yue Zhu
- State
Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics,
National Center for Magnetic Resonance in Wuhan, Wuhan Institute of
Physics and Mathematics, Innovation Academy
for Precision Measurement Science and Technology, Chinese Academy
of Sciences, Wuhan 430071, P. R. China
| | - Qiao Yu
- State
Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics,
National Center for Magnetic Resonance in Wuhan, Wuhan Institute of
Physics and Mathematics, Innovation Academy
for Precision Measurement Science and Technology, Chinese Academy
of Sciences, Wuhan 430071, P. R. China
| | - Zhaoqing Liu
- State
Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics,
National Center for Magnetic Resonance in Wuhan, Wuhan Institute of
Physics and Mathematics, Innovation Academy
for Precision Measurement Science and Technology, Chinese Academy
of Sciences, Wuhan 430071, P. R. China
- University
of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Maosong Qiu
- State
Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics,
National Center for Magnetic Resonance in Wuhan, Wuhan Institute of
Physics and Mathematics, Innovation Academy
for Precision Measurement Science and Technology, Chinese Academy
of Sciences, Wuhan 430071, P. R. China
- University
of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Yu Li
- State
Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics,
National Center for Magnetic Resonance in Wuhan, Wuhan Institute of
Physics and Mathematics, Innovation Academy
for Precision Measurement Science and Technology, Chinese Academy
of Sciences, Wuhan 430071, P. R. China
- University
of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Shizhen Chen
- State
Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics,
National Center for Magnetic Resonance in Wuhan, Wuhan Institute of
Physics and Mathematics, Innovation Academy
for Precision Measurement Science and Technology, Chinese Academy
of Sciences, Wuhan 430071, P. R. China
- University
of Chinese Academy of Sciences, Beijing 100049, P. R. China
- School
of Biomedical Engineering, Hainan University, Haikou, Hainan 570228, P. R. China
| | - Xin Zhou
- State
Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics,
National Center for Magnetic Resonance in Wuhan, Wuhan Institute of
Physics and Mathematics, Innovation Academy
for Precision Measurement Science and Technology, Chinese Academy
of Sciences, Wuhan 430071, P. R. China
- University
of Chinese Academy of Sciences, Beijing 100049, P. R. China
- School
of Biomedical Engineering, Hainan University, Haikou, Hainan 570228, P. R. China
| |
Collapse
|
14
|
Girondi CM, de Castro Lopes SLP, Ogawa CM, Braz-Silva PH, Costa ALF. Texture Analysis of Temporomandibular Joint Disc Changes Associated with Effusion Using Magnetic Resonance Images. Dent J (Basel) 2024; 12:82. [PMID: 38534306 DOI: 10.3390/dj12030082] [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: 01/22/2024] [Revised: 02/27/2024] [Accepted: 03/19/2024] [Indexed: 03/28/2024] Open
Abstract
The purpose of this study was to identify changes in the temporomandibular joint disc affected by effusion by using texture analysis of magnetic resonance images (MRIs). METHODS A total of 223 images of the TMJ, 42 with joint effusion and 181 without, were analyzed. Three consecutive slices were then exported to MaZda software, in which two oval ROIs (one in the anterior band and another in the intermediate zone of the joint disc) were determined in each slice and eleven texture parameters were calculated by using a gray-level co-occurrence matrix. Spearman's correlation coefficient test was used to assess the correlation between texture variables and to select variables for analysis. The Mann-Whitney test was used to compare the groups. RESULTS The significance level was set at 5%, with the results demonstrating that there was no high correlation between the parameter directions. It was possible to observe a trend between the average parameters, in which the group with effusion always had smaller values than the group without effusion, except for the parameter measuring the difference in entropy. CONCLUSION The trend towards lower overall values for the texture parameters suggested a different behavior between TMJ discs affected by effusion and those not affected, indicating that there may be intrinsic changes.
Collapse
Affiliation(s)
- Camila Miorelli Girondi
- Department of Stomatology, School of Dentistry, University of São Paulo (USP), São Paulo 05508-220, SP, Brazil
| | - Sérgio Lúcio Pereira de Castro Lopes
- Department of Diagnosis and Surgery, São José dos Campos School of Dentistry, São Paulo State University (UNESP), São José dos Campos 12245-000, SP, Brazil
| | - Celso Massahiro Ogawa
- Postgraduate Program in Dentistry, Cruzeiro do Sul University (UNICSUL), São Paulo 01506-000, SP, Brazil
| | - Paulo Henrique Braz-Silva
- Department of Stomatology, School of Dentistry, University of São Paulo (USP), São Paulo 05508-220, SP, Brazil
| | - Andre Luiz Ferreira Costa
- Postgraduate Program in Dentistry, Cruzeiro do Sul University (UNICSUL), São Paulo 01506-000, SP, Brazil
| |
Collapse
|
15
|
Gomez DEP, Polimeni JR, Lewis LD. The temporal specificity of BOLD fMRI is systematically related to anatomical and vascular features of the human brain. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.01.578428. [PMID: 38352610 PMCID: PMC10862860 DOI: 10.1101/2024.02.01.578428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/22/2024]
Abstract
The ability to detect fast responses with functional MRI depends on the speed of hemodynamic responses to neural activity, because hemodynamic responses act as a temporal low-pass filter smoothing out rapid changes. However, hemodynamic responses (their shape and timing) are highly variable across the brain and across stimuli. This heterogeneity of responses implies that the temporal specificity of fMRI signals, or the ability of fMRI to preserve fast information, should also vary substantially across the cortex. In this work we investigated how local differences in hemodynamic response timing impact the temporal specificity of fMRI. We conducted our research using ultra-high field (7T) fMRI at high spatiotemporal resolution, using the primary visual cortex (V1) as a model area for investigation. We used visual stimuli oscillating at slow and fast frequencies to probe the temporal specificity of individual voxels. As expected, we identified substantial variability in temporal specificity, with some voxels preserving their responses to fast neural activity more effectively than others. We investigated which voxels had the highest temporal specificity and related those to anatomical and vascular features of V1. We found that low temporal specificity is only weakly explained by the presence of large veins or cerebral cortical depth. Notably, however, temporal specificity depended strongly on a voxel's position along the anterior-posterior anatomical axis of V1, with voxels within the calcarine sulcus being capable of preserving close to 25% of their amplitude as the frequency of stimulation increased from 0.05-Hz to 0.20-Hz, and voxels nearest to the occipital pole preserving less than 18%. These results indicate that detection biases in high-resolution fMRI will depend on the anatomical and vascular features of the area being imaged, and that these biases will differ depending on the timing of the underlying neuronal activity. Importantly, this spatial heterogeneity of temporal specificity suggests that it could be exploited to achieve higher specificity in some locations, and that tailored data analysis strategies may help improve the detection and interpretation of fast fMRI responses.
Collapse
Affiliation(s)
- Daniel E. P. Gomez
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Boston, MA, United States
- Department of Radiology, Harvard Medical School, Boston, MA, United States
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - Jonathan R. Polimeni
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Boston, MA, United States
- Department of Radiology, Harvard Medical School, Boston, MA, United States
- Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - Laura D. Lewis
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Boston, MA, United States
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, United States
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, United States
| |
Collapse
|
16
|
Dong Z, Wald LL, Polimeni JR, Wang F. Single-shot Echo Planar Time-resolved Imaging for multi-echo functional MRI and distortion-free diffusion imaging. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.24.577002. [PMID: 38328081 PMCID: PMC10849706 DOI: 10.1101/2024.01.24.577002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
Purpose To develop EPTI, a multi-shot distortion-free multi-echo imaging technique, into a single-shot acquisition to achieve improved robustness to motion and physiological noise, increased temporal resolution, and high SNR efficiency for dynamic imaging applications. Methods A new spatiotemporal encoding was developed to achieve single-shot EPTI by enhancing spatiotemporal correlation in k-t space. The proposed single-shot encoding improves reconstruction conditioning and sampling efficiency, with additional optimization under various accelerations to achieve optimized performance. To achieve high SNR efficiency, continuous readout with minimized deadtime was employed that begins immediately after excitation and extends for an SNR-optimized length. Moreover, k-t partial Fourier and simultaneous multi-slice acquisition were integrated to further accelerate the acquisition and achieve high spatial and temporal resolution. Results We demonstrated that ss-EPTI achieves higher tSNR efficiency than multi-shot EPTI, and provides distortion-free imaging with densely-sampled multi-echo images at resolutions ~1.25-3 mm at 3T and 7T-with high SNR efficiency and with comparable temporal resolutions to ss-EPI. The ability of ss-EPTI to eliminate dynamic distortions common in EPI also further improves temporal stability. For fMRI, ss-EPTI also provides early-TE images (e.g., 2.9ms) to recover signal-intensity and functional-sensitivity dropout in challenging regions. The multi-echo images provide TE-dependent information about functional fluctuations, successfully distinguishing noise-components from BOLD signals and further improving tSNR. For diffusion MRI, ss-EPTI provides high-quality distortion-free diffusion images and multi-echo diffusion metrics. Conclusion ss-EPTI provides distortion-free imaging with high image quality, rich multi-echo information, and enhanced efficiency within comparable temporal resolution to ss-EPI, offering a robust and efficient acquisition for dynamic imaging.
Collapse
Affiliation(s)
- Zijing Dong
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, USA
- Department of Radiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Lawrence L. Wald
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, USA
- Department of Radiology, Harvard Medical School, Boston, Massachusetts, USA
- Harvard-MIT Health Sciences and Technology, MIT, Cambridge, Massachusetts, USA
| | - Jonathan R. Polimeni
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, USA
- Department of Radiology, Harvard Medical School, Boston, Massachusetts, USA
- Harvard-MIT Health Sciences and Technology, MIT, Cambridge, Massachusetts, USA
| | - Fuyixue Wang
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, USA
- Department of Radiology, Harvard Medical School, Boston, Massachusetts, USA
| |
Collapse
|