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Versteeg E, Liu H, van der Heide O, Fuderer M, van den Berg CAT, Sbrizzi A. High SNR full brain relaxometry at 7T by accelerated MR-STAT. Magn Reson Med 2024; 92:226-235. [PMID: 38326909 DOI: 10.1002/mrm.30052] [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: 11/01/2023] [Revised: 12/21/2023] [Accepted: 01/26/2024] [Indexed: 02/09/2024]
Abstract
PURPOSE To demonstrate the feasibility and robustness of the Magnetic Resonance Spin TomogrAphy in Time-domain (MR-STAT) framework for fast, high SNR relaxometry at 7T. METHODS To deploy MR-STAT on 7T-systems, we designed optimized flip-angles using the BLAKJac-framework that incorporates the SAR-constraints. Transmit RF-inhomogeneities were mitigated by including a measuredB 1 + $$ {B}_1^{+} $$ -map in the reconstruction. Experiments were performed on a gel-phantom and on five volunteers to explore the robustness of the sequence and its sensitivity toB 1 + $$ {B}_1^{+} $$ inhomogeneities. The SNR-gain at 7T was explored by comparing phantom and in vivo results to MR-STAT at 3T in terms of SNR-efficiency. RESULTS The higher SNR at 7T enabled two-fold acceleration with respect to current 2D MR-STAT protocols at lower field strengths. The resulting scan had whole-brain coverage, with 1 x 1 x 3 mm3 resolution (1.5 mm slice-gap) and was acquired within 3 min including theB 1 + $$ {B}_1^{+} $$ -mapping. AfterB 1 + $$ {B}_1^{+} $$ -correction, the estimated T1 and T2 in a phantom showed a mean relative error of, respectively, 1.7% and 4.4%. In vivo, the estimated T1 and T2 in gray and white matter corresponded to the range of values reported in literature with a variation over the subjects of 1.0%-2.1% (WM-GM) for T1 and 4.3%-5.3% (WM-GM) for T2. We measured a higher SNR-efficiency at 7T (R = 2) than at 3T for both T1 and T2 with, respectively, a 4.1 and 2.3 times increase in SNR-efficiency. CONCLUSION We presented an accelerated version of MR-STAT tailored to high field (7T) MRI using a low-SAR flip-angle train and showed high quality parameter maps with an increased SNR-efficiency compared to MR-STAT at 3T.
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Affiliation(s)
- Edwin Versteeg
- Computational Imaging Group, Department of Radiotherapy, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Hongyan Liu
- Computational Imaging Group, Department of Radiotherapy, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Oscar van der Heide
- Computational Imaging Group, Department of Radiotherapy, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Miha Fuderer
- Computational Imaging Group, Department of Radiotherapy, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Cornelis A T van den Berg
- Computational Imaging Group, Department of Radiotherapy, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Alessandro Sbrizzi
- Computational Imaging Group, Department of Radiotherapy, University Medical Center Utrecht, Utrecht, The Netherlands
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Ding Z, Hu S, Su TY, Choi JY, Morris S, Wang X, Sakaie K, Murakami H, Huppertz HJ, Blümcke I, Jones S, Najm I, Ma D, Wang ZI. Combining magnetic resonance fingerprinting with voxel-based morphometric analysis to reduce false positives for focal cortical dysplasia detection. Epilepsia 2024; 65:1631-1643. [PMID: 38511905 PMCID: PMC11166521 DOI: 10.1111/epi.17951] [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: 10/31/2023] [Revised: 02/09/2024] [Accepted: 03/04/2024] [Indexed: 03/22/2024]
Abstract
OBJECTIVE We aim to improve focal cortical dysplasia (FCD) detection by combining high-resolution, three-dimensional (3D) magnetic resonance fingerprinting (MRF) with voxel-based morphometric magnetic resonance imaging (MRI) analysis. METHODS We included 37 patients with pharmacoresistant focal epilepsy and FCD (10 IIa, 15 IIb, 10 mild Malformation of Cortical Development [mMCD], and 2 mMCD with oligodendroglial hyperplasia and epilepsy [MOGHE]). Fifty-nine healthy controls (HCs) were also included. 3D lesion labels were manually created. Whole-brain MRF scans were obtained with 1 mm3 isotropic resolution, from which quantitative T1 and T2 maps were reconstructed. Voxel-based MRI postprocessing, implemented with the morphometric analysis program (MAP18), was performed for FCD detection using clinical T1w images, outputting clusters with voxel-wise lesion probabilities. Average MRF T1 and T2 were calculated in each cluster from MAP18 output for gray matter (GM) and white matter (WM) separately. Normalized MRF T1 and T2 were calculated by z-scores using HCs. Clusters that overlapped with the lesion labels were considered true positives (TPs); clusters with no overlap were considered false positives (FPs). Two-sample t-tests were performed to compare MRF measures between TP/FP clusters. A neural network model was trained using MRF values and cluster volume to distinguish TP/FP clusters. Ten-fold cross-validation was used to evaluate model performance at the cluster level. Leave-one-patient-out cross-validation was used to evaluate performance at the patient level. RESULTS MRF metrics were significantly higher in TP than FP clusters, including GM T1, normalized WM T1, and normalized WM T2. The neural network model with normalized MRF measures and cluster volume as input achieved mean area under the curve (AUC) of .83, sensitivity of 82.1%, and specificity of 71.7%. This model showed superior performance over direct thresholding of MAP18 FCD probability map at both the cluster and patient levels, eliminating ≥75% FP clusters in 30% of patients and ≥50% of FP clusters in 91% of patients. SIGNIFICANCE This pilot study suggests the efficacy of MRF for reducing FPs in FCD detection, due to its quantitative values reflecting in vivo pathological changes. © 2024 International League Against Epilepsy.
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Affiliation(s)
- Zheng Ding
- Epilepsy Center, Neurological Institute - Cleveland Clinic, Cleveland, Ohio
- Biomedical Engineering - Case Western Reserve University, Cleveland, Ohio
| | - Siyuan Hu
- Biomedical Engineering - Case Western Reserve University, Cleveland, Ohio
| | - Ting-Yu Su
- Epilepsy Center, Neurological Institute - Cleveland Clinic, Cleveland, Ohio
- Biomedical Engineering - Case Western Reserve University, Cleveland, Ohio
| | - Joon Yul Choi
- Epilepsy Center, Neurological Institute - Cleveland Clinic, Cleveland, Ohio
- Biomedical Engineering - Yonsei University, Wonju, Republic of Korea
| | - Spencer Morris
- Epilepsy Center, Neurological Institute - Cleveland Clinic, Cleveland, Ohio
- Biomedical Engineering - Case Western Reserve University, Cleveland, Ohio
| | - Xiaofeng Wang
- Quantitative Health Science - Cleveland Clinic, Cleveland, Ohio
| | - Ken Sakaie
- Imaging Institute - Cleveland Clinic, Cleveland, Ohio
| | - Hiroatsu Murakami
- Epilepsy Center, Neurological Institute - Cleveland Clinic, Cleveland, Ohio
| | | | - Ingmar Blümcke
- Epilepsy Center, Neurological Institute - Cleveland Clinic, Cleveland, Ohio
- Neuropathology - University Hospital Erlangen, Erlangen, Germany
| | - Stephen Jones
- Imaging Institute - Cleveland Clinic, Cleveland, Ohio
| | - Imad Najm
- Epilepsy Center, Neurological Institute - Cleveland Clinic, Cleveland, Ohio
| | - Dan Ma
- Biomedical Engineering - Case Western Reserve University, Cleveland, Ohio
| | - Zhong Irene Wang
- Epilepsy Center, Neurological Institute - Cleveland Clinic, Cleveland, Ohio
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3
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Li T, Wang J, Yang Y, Glide-Hurst CK, Wen N, Cai J. Multi-parametric MRI for radiotherapy simulation. Med Phys 2023; 50:5273-5293. [PMID: 36710376 PMCID: PMC10382603 DOI: 10.1002/mp.16256] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 09/10/2022] [Accepted: 12/06/2022] [Indexed: 01/31/2023] Open
Abstract
Magnetic resonance imaging (MRI) has become an important imaging modality in the field of radiotherapy (RT) in the past decade, especially with the development of various novel MRI and image-guidance techniques. In this review article, we will describe recent developments and discuss the applications of multi-parametric MRI (mpMRI) in RT simulation. In this review, mpMRI refers to a general and loose definition which includes various multi-contrast MRI techniques. Specifically, we will focus on the implementation, challenges, and future directions of mpMRI techniques for RT simulation.
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Affiliation(s)
- Tian Li
- Department of Health Technology and Informatics, The Hong Kong Polytechnic University, Hong Kong, China
| | - Jihong Wang
- Department of Radiation Physics, Division of Radiation Oncology, MD Anderson Cancer Center, Houston, Texas, USA
| | - Yingli Yang
- Department of Radiology, Ruijin Hospital, Shanghai Jiaotong Univeristy School of Medicine, Shanghai, China
- SJTU-Ruijing-UIH Institute for Medical Imaging Technology, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Carri K Glide-Hurst
- Department of Radiation Oncology, University of Wisconsin, Madison, Wisconsin, USA
| | - Ning Wen
- Department of Radiology, Ruijin Hospital, Shanghai Jiaotong Univeristy School of Medicine, Shanghai, China
- SJTU-Ruijing-UIH Institute for Medical Imaging Technology, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
- The Global Institute of Future Technology, Shanghai Jiaotong University, Shanghai, China
| | - Jing Cai
- Department of Health Technology and Informatics, The Hong Kong Polytechnic University, Hong Kong, China
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4
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Kang B, Singh M, Park H, Heo HY. Only-train-once MR fingerprinting for B 0 and B 1 inhomogeneity correction in quantitative magnetization-transfer contrast. Magn Reson Med 2023; 90:90-102. [PMID: 36883726 PMCID: PMC10149616 DOI: 10.1002/mrm.29629] [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: 09/29/2022] [Revised: 02/15/2023] [Accepted: 02/16/2023] [Indexed: 03/09/2023]
Abstract
PURPOSE To develop a fast, deep-learning approach for quantitative magnetization-transfer contrast (MTC)-MR fingerprinting (MRF) that simultaneously estimates multiple tissue parameters and corrects the effects of B0 and B1 variations. METHODS An only-train-once recurrent neural network was designed to perform the fast tissue-parameter quantification for a large range of different MRF acquisition schedules. It enabled a dynamic scan-wise linear calibration of the scan parameters using the measured B0 and B1 maps, which allowed accurate, multiple-tissue parameter mapping. MRF images were acquired from 8 healthy volunteers at 3 T. Estimated parameter maps from the MRF images were used to synthesize the MTC reference signal (Zref ) through Bloch equations at multiple saturation power levels. RESULTS The B0 and B1 errors in MR fingerprints, if not corrected, would impair the tissue quantification and subsequently corrupt the synthesized MTC reference images. Bloch equation-based numerical phantom studies and synthetic MRI analysis demonstrated that the proposed approach could correctly estimate water and semisolid macromolecule parameters, even with severe B0 and B1 inhomogeneities. CONCLUSION The only-train-once deep-learning framework can improve the reconstruction accuracy of brain-tissue parameter maps and be further combined with any conventional MRF or CEST-MRF method.
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Affiliation(s)
- Beomgu Kang
- School of Electrical Engineering, Korea Advanced Institute of Science and Technology, Guseong-dong, Yuseong-gu, Daejeon, Republic of Korea
- Divison of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA
| | - Munendra Singh
- Divison of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA
| | - HyunWook Park
- School of Electrical Engineering, Korea Advanced Institute of Science and Technology, Guseong-dong, Yuseong-gu, Daejeon, Republic of Korea
| | - Hye-Young Heo
- Divison of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA
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5
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Axford A, Grist JT. Editorial for "Age-Dependent Changes in Knee Cartilage T 1 , T 2 , and T 1p Simultaneously Measured Using MRI Fingerprinting". J Magn Reson Imaging 2023; 57:1813-1814. [PMID: 36173385 DOI: 10.1002/jmri.28458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Accepted: 09/20/2022] [Indexed: 11/10/2022] Open
Affiliation(s)
- Aaron Axford
- Oxford Centre for Clinical Magnetic Resonance Research, University of Oxford, Oxford, UK
| | - James T Grist
- Oxford Centre for Clinical Magnetic Resonance Research, University of Oxford, Oxford, UK
- Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford, UK
- Department of Radiology, Oxford University Hospitals, Oxford, UK
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, UK
- University of Bologna Alama Mata Studorium, Bologna, Italy
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6
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Cartesian vs radial MR-STAT: An efficiency and robustness study. Magn Reson Imaging 2023; 99:7-19. [PMID: 36709010 DOI: 10.1016/j.mri.2023.01.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 10/21/2022] [Accepted: 01/14/2023] [Indexed: 01/27/2023]
Abstract
MR Spin TomogrAphy in Time-domain ("MR-STAT") is quantitative MR technique in which multiple quantitative parameters are estimated from a single short scan by solving a large-scale non-linear optimization problem. In this work we extended the MR-STAT framework to non-Cartesian gradient trajectories. Cartesian MR-STAT and radial MR-STAT were compared in terms of time-efficiency and robustness in simulations, gel phantom measurements and in vivo measurements. In simulations, we observed that both Cartesian and radial MR-STAT are highly robust against undersampling. Radial MR-STAT does have a lower spatial encoding power because the outer corners of k-space are never sampled. However, especially in T2, this is compensated by a higher dynamic encoding power that comes from sampling the k-space center with each readout. In gel phantom measurements, Cartesian MR-STAT was observed to be robust against overfitting whereas radial MR-STAT suffered from high-frequency artefacts in the parameter maps at later iterations. These artefacts are hypothesized to be related to hardware imperfections and were (partially) suppressed with image filters. The time-efficiencies were higher for Cartesian MR-STAT in all vials. In-vivo, the radial reconstruction again suffered from overfitting artefacts. The robustness of Cartesian MR-STAT over the entire range of experiments may make it preferable in a clinical setting, despite radial MR-STAT resulting in a higher T1 time-efficiency in white matter.
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Nassar J, Trabelsi A, Amer R, Le Fur Y, Attarian S, Radunsky D, Blumenfeld-Katzir T, Greenspan H, Bendahan D, Ben-Eliezer N. Estimation of subvoxel fat infiltration in neurodegenerative muscle disorders using quantitative multi-T 2 analysis. NMR IN BIOMEDICINE 2023:e4947. [PMID: 37021657 DOI: 10.1002/nbm.4947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Revised: 02/13/2023] [Accepted: 03/21/2023] [Indexed: 06/19/2023]
Abstract
MRI's T2 relaxation time is a valuable biomarker for neuromuscular disorders and muscle dystrophies. One of the hallmarks of these pathologies is the infiltration of adipose tissue and a loss of muscle volume. This leads to a mixture of two signal components, from fat and from water, to appear in each imaged voxel, each having a specific T2 relaxation time. In this proof-of-concept work, we present a technique that can separate the signals from water and from fat within each voxel, measure their separate T2 values, and calculate their relative fractions. The echo modulation curve (EMC) algorithm is a dictionary-based technique that offers accurate and reproducible mapping of T2 relaxation times. We present an extension of the EMC algorithm for estimating subvoxel fat and water fractions, alongside the T2 and proton-density values of each component. To facilitate data processing, calf and thigh anatomy were automatically segmented using a fully convolutional neural network and FSLeyes software. The preprocessing included creating two signal dictionaries, for water and for fat, using Bloch simulations of the prospective protocol. Postprocessing included voxelwise fitting for two components, by matching the experimental decay curve to a linear combination of the two simulated dictionaries. Subvoxel fat and water fractions and relaxation times were generated and used to calculate a new quantitative biomarker, termed viable muscle index, and reflecting disease severity. This biomarker indicates the fraction of remaining muscle out of the entire muscle region. The results were compared with those using the conventional Dixon technique, showing high agreement (R = 0.98, p < 0.001). It was concluded that the new extension of the EMC algorithm can be used to quantify abnormal fat infiltration as well as identify early inflammatory processes corresponding to elevation in the T2 value of the water (muscle) component. This new ability may improve the diagnostic accuracy of neuromuscular diseases, help stratification of patients according to disease severity, and offer an efficient tool for tracking disease progression.
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Affiliation(s)
- Jannette Nassar
- Department of Biomedical Engineering, Tel Aviv University, Tel Aviv, Israel
| | | | - Rula Amer
- Department of Biomedical Engineering, Tel Aviv University, Tel Aviv, Israel
| | | | - Shahram Attarian
- Reference Center for Neuromuscular Diseases and ALS, La Timone University Hospital, Aix-Marseille University, Marseille, France
- Inserm, GMGF, Aix Marseille University, Marseille, France
| | - Dvir Radunsky
- Department of Biomedical Engineering, Tel Aviv University, Tel Aviv, Israel
| | | | - Hayit Greenspan
- Department of Biomedical Engineering, Tel Aviv University, Tel Aviv, Israel
| | | | - Noam Ben-Eliezer
- Department of Biomedical Engineering, Tel Aviv University, Tel Aviv, Israel
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
- Center for Advanced Imaging Innovation and Research, New York University Langone Medical Center, New York, New York, USA
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8
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Fujita S, Cencini M, Buonincontri G, Takei N, Schulte RF, Fukunaga I, Uchida W, Hagiwara A, Kamagata K, Hagiwara Y, Matsuyama Y, Abe O, Tosetti M, Aoki S. Simultaneous relaxometry and morphometry of human brain structures with 3D magnetic resonance fingerprinting: a multicenter, multiplatform, multifield-strength study. Cereb Cortex 2022; 33:729-739. [PMID: 35271703 PMCID: PMC9890456 DOI: 10.1093/cercor/bhac096] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 02/10/2022] [Accepted: 02/12/2022] [Indexed: 02/04/2023] Open
Abstract
Relaxation times and morphological information are fundamental magnetic resonance imaging-derived metrics of the human brain that reflect the status of the underlying tissue. Magnetic resonance fingerprinting (MRF) enables simultaneous acquisition of T1 and T2 maps inherently aligned to the anatomy, allowing whole-brain relaxometry and morphometry in a single scan. In this study, we revealed the feasibility of 3D MRF for simultaneous brain structure-wise morphometry and relaxometry. Comprehensive test-retest scan analyses using five 1.5-T and three 3.0-T systems from a single vendor including different scanner types across 3 institutions demonstrated that 3D MRF-derived morphological information and relaxation times are highly repeatable at both 1.5 T and 3.0 T. Regional cortical thickness and subcortical volume values showed high agreement and low bias across different field strengths. The ability to acquire a set of regional T1, T2, thickness, and volume measurements of neuroanatomical structures with high repeatability and reproducibility facilitates the ability of longitudinal multicenter imaging studies to quantitatively monitor changes associated with underlying pathologies, disease progression, and treatments.
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Affiliation(s)
- Shohei Fujita
- Corresponding author: Department of Radiology, Juntendo University School of Medicine, 12-1 Hongo, Bunkyo, Tokyo 113-8421, Japan.
| | - Matteo Cencini
- Imago7 Foundation, Pisa, Italy,IRCCS Stella Maris, Pisa, Italy
| | | | | | | | - Issei Fukunaga
- Department of Radiology, Juntendo University, Tokyo, Japan
| | - Wataru Uchida
- Department of Radiology, Juntendo University, Tokyo, Japan
| | | | - Koji Kamagata
- Department of Radiology, Juntendo University, Tokyo, Japan
| | - Yasuhiro Hagiwara
- Department of Biostatistics, School of Public Health, The University of Tokyo, Tokyo, Japan
| | - Yutaka Matsuyama
- Department of Biostatistics, School of Public Health, The University of Tokyo, Tokyo, Japan
| | - Osamu Abe
- Department of Radiology, The University of Tokyo, Tokyo, Japan
| | - Michela Tosetti
- Imago7 Foundation, Pisa, Italy,IRCCS Stella Maris, Pisa, Italy
| | - Shigeki Aoki
- Department of Radiology, Juntendo University, Tokyo, Japan
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Cao X, Liao C, Iyer SS, Wang Z, Zhou Z, Dai E, Liberman G, Dong Z, Gong T, He H, Zhong J, Bilgic B, Setsompop K. Optimized multi-axis spiral projection MR fingerprinting with subspace reconstruction for rapid whole-brain high-isotropic-resolution quantitative imaging. Magn Reson Med 2022; 88:133-150. [PMID: 35199877 DOI: 10.1002/mrm.29194] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 12/16/2021] [Accepted: 01/21/2022] [Indexed: 11/07/2022]
Abstract
PURPOSE To improve image quality and accelerate the acquisition of 3D MR fingerprinting (MRF). METHODS Building on the multi-axis spiral-projection MRF technique, a subspace reconstruction with locally low-rank constraint and a modified spiral-projection spatiotemporal encoding scheme called tiny golden-angle shuffling were implemented for rapid whole-brain high-resolution quantitative mapping. Reconstruction parameters such as the locally low-rank regularization parameter and the subspace rank were tuned using retrospective in vivo data and simulated examinations. B0 inhomogeneity correction using multifrequency interpolation was incorporated into the subspace reconstruction to further improve the image quality by mitigating blurring caused by off-resonance effect. RESULTS The proposed MRF acquisition and reconstruction framework yields high-quality 1-mm isotropic whole-brain quantitative maps in 2 min at better quality compared with 6-min acquisitions of prior approaches. The proposed method was validated to not induce bias in T1 and T2 mapping. High-quality whole-brain MRF data were also obtained at 0.66-mm isotropic resolution in 4 min using the proposed technique, where the increased resolution was shown to improve visualization of subtle brain structures. CONCLUSIONS The proposed tiny golden-angle shuffling, MRF with optimized spiral-projection trajectory and subspace reconstruction enables high-resolution quantitative mapping in ultrafast acquisition time.
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Affiliation(s)
- Xiaozhi Cao
- Department of Radiology, Stanford University, Stanford, California, USA.,Department of Electrical Engineering, Stanford University, Stanford, California, USA
| | - Congyu Liao
- Department of Radiology, Stanford University, Stanford, California, USA.,Department of Electrical Engineering, Stanford University, Stanford, California, USA
| | - Siddharth Srinivasan Iyer
- Department of Radiology, Stanford University, Stanford, California, USA.,Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, USA.,Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Zhixing Wang
- Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia, USA
| | - Zihan Zhou
- Center for Brain Imaging Science and Technology, College of Biomedical Engineering and Instrumental Science, Zhejiang University, Hangzhou, China
| | - Erpeng Dai
- Department of Radiology, Stanford University, Stanford, California, USA
| | - Gilad Liberman
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, USA
| | - Zijing Dong
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, USA.,Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Ting Gong
- Center for Brain Imaging Science and Technology, College of Biomedical Engineering and Instrumental Science, Zhejiang University, Hangzhou, China
| | - Hongjian He
- Center for Brain Imaging Science and Technology, College of Biomedical Engineering and Instrumental Science, Zhejiang University, Hangzhou, China
| | - Jianhui Zhong
- Center for Brain Imaging Science and Technology, College of Biomedical Engineering and Instrumental Science, Zhejiang University, Hangzhou, China.,Department of Imaging Sciences, University of Rochester, Rochester, New York, USA
| | - Berkin Bilgic
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, USA.,Department of Radiology, Harvard Medical School, Cambridge, Massachusetts, USA.,Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Kawin Setsompop
- Department of Radiology, Stanford University, Stanford, California, USA.,Department of Electrical Engineering, Stanford University, Stanford, California, USA
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10
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Gu Y, Wang L, Yang H, Wu Y, Kim K, Zhu Y, Androjna C, Zhu X, Chen Y, Zhong K, Yu X. Three-dimensional high-resolution T 1 and T 2 mapping of whole macaque brain at 9.4 T using magnetic resonance fingerprinting. Magn Reson Med 2022; 87:2901-2913. [PMID: 35129226 DOI: 10.1002/mrm.29181] [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: 12/08/2021] [Revised: 01/10/2022] [Accepted: 01/10/2022] [Indexed: 11/12/2022]
Abstract
PURPOSE Quantitative T1 and T2 mapping in non-human primates with whole-brain coverage is challenged by the requirement of sub-millimeter resolution and the inhomogeneity of the transmit magnetic field (B1 + ) covering a large field of view. The goal of the current study is to develop a magnetic resonance fingerprinting (MRF) method for simultaneous T1 and T2 mapping of the entire macaque brain within feasible scan time. METHODS A three-dimensional (3D) MRF sequence with both inversion- and T2 -preparation modules was developed and evaluated on a 9.4 T preclinical scanner. Data acquisition used a 3D stack-of-spirals trajectory, with undersampling along both the in-plane and the through-plane directions. The effect of B1 + inhomogeneity was accounted for by matching the acquired fingerprint to a dictionary simulated with the B1 + factors measured from a separate scan. In vitro and ex vivo studies were performed to evaluate the accuracy and the undersampling capacity of the MRF method. The application of the MRF method for in vivo, brain-wide T1 and T2 mapping was demonstrated on macaques at 4, 6, and 12 years of age. RESULTS The MRF method enabled highly repeatable T1 and T2 mapping at high spatial resolution (0.35 × 0.35 × 1 mm3 ) with an acceleration factor of 24. In vivo studies showed significant age-related T2 reduction in deep gray nuclei including the globus pallidus, the putamen, and the caudate nucleus. CONCLUSIONS This study demonstrates the first MRF study for brain-wide, multi-parametric quantification in non-human primates with sub-millimeter resolution.
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Affiliation(s)
- Yuning Gu
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio, USA
| | - Lulu Wang
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, China.,Anhui Province Key Laboratory of High Field Magnetic Resonance Imaging, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, China
| | - Hongyi Yang
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, China.,Anhui Province Key Laboratory of High Field Magnetic Resonance Imaging, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, China.,School of Graduate Studies, Science Island Branch, University of Science and Technology of China, Hefei, China
| | - Yun Wu
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, China.,Anhui Province Key Laboratory of High Field Magnetic Resonance Imaging, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, China
| | - Kihwan Kim
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio, USA
| | - Yuran Zhu
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio, USA
| | - Charlie Androjna
- Center for Preclinical Magnetic Resonance Imaging, Cleveland Clinic Foundation, Cleveland, Ohio, USA
| | - Xiaofeng Zhu
- Department of Epidemiology and Biostatistics, Case Western Reserve University, Cleveland, Ohio, USA
| | - Yong Chen
- Department of Radiology, Case Western Reserve University, Cleveland, Ohio, USA
| | - Kai Zhong
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, China.,Anhui Province Key Laboratory of High Field Magnetic Resonance Imaging, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, China.,Biomedical Engineering Department, Peking University, Beijing, China
| | - Xin Yu
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio, USA.,Department of Radiology, Case Western Reserve University, Cleveland, Ohio, USA
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11
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Coronado R, Cruz G, Castillo-Passi C, Tejos C, Uribe S, Prieto C, Irarrazaval P. A Spatial Off-Resonance Correction in Spirals for Magnetic Resonance Fingerprinting. IEEE TRANSACTIONS ON MEDICAL IMAGING 2021; 40:3832-3842. [PMID: 34310296 DOI: 10.1109/tmi.2021.3100293] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
In MR Fingerprinting (MRF), balanced Steady-State Free Precession (bSSFP) has advantages over unbalanced SSFP because it retains the spin history achieving a higher signal-to-noise ratio (SNR) and scan efficiency. However, bSSFP-MRF is not frequently used because it is sensitive to off-resonance, producing artifacts and blurring, and affecting the parametric map quality. Here we propose a novel Spatial Off-resonance Correction (SOC) approach for reducing these artifacts in bSSFP-MRF with spiral trajectories. SOC-MRF uses each pixel's Point Spread Function to create system matrices that encode both off-resonance and gridding effects. We iteratively compute the inverse of these matrices to reduce the artifacts. We evaluated the proposed method using brain simulations and actual MRF acquisitions of a standardized T1/T2 phantom and five healthy subjects. The results show that the off-resonance distortions in T1/T2 maps were considerably reduced using SOC-MRF. For T2, the Normalized Root Mean Square Error (NRMSE) was reduced from 17.3 to 8.3% (simulations) and from 35.1 to 14.9% (phantom). For T1, the NRMS was reduced from 14.7 to 7.7% (simulations) and from 17.7 to 6.7% (phantom). For in-vivo, the mean and standard deviation in different ROI in white and gray matter were significantly improved. For example, SOC-MRF estimated an average T2 for white matter of 77ms (the ground truth was 74ms) versus 50 ms of MRF. For the same example the standard deviation was reduced from 18 ms to 6ms. The corrections achieved with the proposed SOC-MRF may expand the potential applications of bSSFP-MRF, taking advantage of its better SNR property.
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12
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Abstract
Magnetic resonance fingerprinting (MRF) is increasingly being used to evaluate brain development and differentiate normal and pathologic tissues in children. MRF can provide reliable and accurate intrinsic tissue properties, such as T1 and T2 relaxation times. MRF is a powerful tool in evaluating brain disease in pediatric population. MRF is a new quantitative MR imaging technique for rapid and simultaneous quantification of multiple tissue properties.
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Affiliation(s)
- Sheng-Che Hung
- Department of Radiology, School of Medicine, University of North Carolina at Chapel Hill, 2006 Old Clinic, CB#7510, 101 Manning Dr, Chapel Hill, NC 27599, USA; Biomedical Research Imaging Center, School of Medicine, University of North Carolina at Chapel Hill, 125 Mason Farm Road, Marsico Hall, suite 1200, Chapel Hill, NC 27599, USA
| | - Yong Chen
- Department of Radiology, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA
| | - Pew-Thian Yap
- Department of Radiology, School of Medicine, University of North Carolina at Chapel Hill, 2006 Old Clinic, CB#7510, 101 Manning Dr, Chapel Hill, NC 27599, USA; Biomedical Research Imaging Center, School of Medicine, University of North Carolina at Chapel Hill, 125 Mason Farm Road, Marsico Hall, suite 1200, Chapel Hill, NC 27599, USA
| | - Weili Lin
- Department of Radiology, School of Medicine, University of North Carolina at Chapel Hill, 2006 Old Clinic, CB#7510, 101 Manning Dr, Chapel Hill, NC 27599, USA; Biomedical Research Imaging Center, School of Medicine, University of North Carolina at Chapel Hill, 125 Mason Farm Road, Marsico Hall, suite 1200, Chapel Hill, NC 27599, USA.
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13
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From signal-based to comprehensive magnetic resonance imaging. Sci Rep 2021; 11:17216. [PMID: 34446804 PMCID: PMC8390767 DOI: 10.1038/s41598-021-96791-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 08/09/2021] [Indexed: 12/03/2022] Open
Abstract
We present and evaluate a new insight into magnetic resonance imaging (MRI). It is based on the algebraic description of the magnetization during the transient response—including intrinsic magnetic resonance parameters such as longitudinal and transverse relaxation times (T1, T2) and proton density (PD) and experimental conditions such as radiofrequency field (B1) and constant/homogeneous magnetic field (B0) from associated scanners. We exploit the correspondence among three different elements: the signal evolution as a result of a repetitive sequence of blocks of radiofrequency excitation pulses and encoding gradients, the continuous Bloch equations and the mathematical description of a sequence as a linear system. This approach simultaneously provides, in a single measurement, all quantitative parameters of interest as well as associated system imperfections. Finally, we demonstrate the in-vivo applicability of the new concept on a clinical MRI scanner.
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14
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Liu H, van der Heide O, van den Berg CAT, Sbrizzi A. Fast and accurate modeling of transient-state, gradient-spoiled sequences by recurrent neural networks. NMR IN BIOMEDICINE 2021; 34:e4527. [PMID: 33949718 PMCID: PMC8244023 DOI: 10.1002/nbm.4527] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 03/26/2021] [Indexed: 05/11/2023]
Abstract
Fast and accurate modeling of MR signal responses are typically required for various quantitative MRI applications, such as MR fingerprinting. This work uses a new extended phase graph (EPG)-Bloch model for accurate simulation of transient-state, gradient-spoiled MR sequences, and proposes a recurrent neural network (RNN) as a fast surrogate of the EPG-Bloch model for computing large-scale MR signals and derivatives. The computational efficiency of the RNN model is demonstrated by comparisons with other existing models, showing one to three orders of acceleration compared with the latest GPU-accelerated, open-source EPG package. By using numerical and in vivo brain data, two used cases, namely, MRF dictionary generation and optimal experimental design, are also provided. Results show that the RNN surrogate model can be efficiently used for computing large-scale dictionaries of transient-state signals and derivatives within tens of seconds, resulting in several orders of magnitude acceleration with respect to state-of-the-art implementations. The practical application of transient-state quantitative techniques can therefore be substantially facilitated.
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Affiliation(s)
- Hongyan Liu
- Center for Image SciencesUniversity Medical Center UtrechtUtrechtthe Netherlands
| | - Oscar van der Heide
- Center for Image SciencesUniversity Medical Center UtrechtUtrechtthe Netherlands
| | | | - Alessandro Sbrizzi
- Center for Image SciencesUniversity Medical Center UtrechtUtrechtthe Netherlands
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15
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Khajehim M, Christen T, Tam F, Graham SJ. Streamlined magnetic resonance fingerprinting: Fast whole-brain coverage with deep-learning based parameter estimation. Neuroimage 2021; 238:118237. [PMID: 34091035 DOI: 10.1016/j.neuroimage.2021.118237] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 05/26/2021] [Accepted: 06/02/2021] [Indexed: 01/02/2023] Open
Abstract
Magnetic resonance fingerprinting (MRF) is a quantitative MRI (qMRI) framework that provides simultaneous estimates of multiple relaxation parameters as well as metrics of field inhomogeneity in a single acquisition. However, current challenges exist in the forms of (1) scan time; (2) need for custom image reconstruction; (3) large dictionary sizes; (4) long dictionary-matching time. This study aims to introduce a novel streamlined magnetic-resonance fingerprinting (sMRF) framework based on a single-shot echo-planar imaging (EPI) sequence to simultaneously estimate tissue T1, T2, and T2* with integrated B1+ correction. Encouraged by recent work on EPI-based MRF, we developed a method that combines spin-echo EPI with gradient-echo EPI to achieve T2 in addition to T1 and T2* quantification. To this design, we add simultaneous multi-slice (SMS) acceleration to enable full-brain coverage in a few minutes. Moreover, in the parameter-estimation step, we use deep learning to train a deep neural network (DNN) to accelerate the estimation process by orders of magnitude. Notably, due to the high image quality of the EPI scans, the training process can rely simply on Bloch-simulated data. The DNN also removes the need for storing large dictionaries. Phantom scans along with in-vivo multi-slice scans from seven healthy volunteers were acquired with resolutions of 1.1×1.1×3 mm3 and 1.7×1.7×3 mm3, and the results were validated against ground truth measurements. Excellent correspondence was found between our T1, T2, and T2* estimates and results obtained from standard approaches. In the phantom scan, a strong linear relationship (R = 1-1.04, R2>0.96) was found for all parameter estimates, with a particularly high agreement for T2 estimation (R2>0.99). Similar findings are reported for the in-vivo human data for all of our parameter estimates. Incorporation of DNN results in a reduction of parameter estimation time on the order of 1000 x and a reduction in storage requirements on the order of 2500 x while achieving highly similar results as conventional dictionary matching (%differences of 7.4 ± 0.4%, 3.6 ± 0.3% and 6.0 ± 0.4% error in T1, T2, and T2* estimation). Thus, sMRF has the potential to be the method of choice for future MRF studies by providing ease of implementation, fast whole-brain coverage, and ultra-fast T1/T2/T2* estimation.
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Affiliation(s)
- Mahdi Khajehim
- Department of Medical Biophysics, University of Toronto, 101 College St Suite 15-701, Toronto, ON M5G 1L7, Canada.
| | - Thomas Christen
- Grenoble Institute of Neuroscience, Inserm, Grenoble, France
| | - Fred Tam
- Hurvitz Brain Sciences Research Program, Sunnybrook Research Institute, Toronto, ON, Canada
| | - Simon J Graham
- Department of Medical Biophysics, University of Toronto, 101 College St Suite 15-701, Toronto, ON M5G 1L7, Canada; Hurvitz Brain Sciences Research Program, Sunnybrook Research Institute, Toronto, ON, Canada
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16
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Kiselev VG, Körzdörfer G, Gall P. Toward Quantification: Microstructure and Magnetic Resonance Fingerprinting. Invest Radiol 2021; 56:1-9. [PMID: 33186141 DOI: 10.1097/rli.0000000000000738] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Quantitative magnetic resonance imaging (MRI) is a long-standing challenge. We advocate that the origin of the problem is the simplification applied in commonly used models of the MRI signal relation to the target parameters of biological tissues. Two research fields are briefly reviewed as ways to respond to the challenge of quantitative MRI, both experiencing an exponential growth right now. Microstructure MRI strives to build physiology-based models from cells to signal and, given the signal, back to the cells again. Magnetic resonance fingerprinting aims at efficient simultaneous determination of multiple signal parameters. The synergy of these yet disjoined approaches promises truly quantitative MRI with specific target-oriented diagnostic tools rather than universal imaging methods.
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Affiliation(s)
- Valerij G Kiselev
- From the Medical Physics, Department of Radiology, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg
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17
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Boyacioglu R, Wang C, Ma D, McGivney DF, Yu X, Griswold MA. 3D magnetic resonance fingerprinting with quadratic RF phase. Magn Reson Med 2020; 85:2084-2094. [PMID: 33179822 DOI: 10.1002/mrm.28581] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 09/25/2020] [Accepted: 10/12/2020] [Indexed: 12/26/2022]
Abstract
PURPOSE To implement 3D magnetic resonance fingerprinting (MRF) with quadratic RF phase (qRF-MRF) for simultaneous quantification of T1 , T2 , ΔB0 , and T 2 ∗ . METHODS 3D MRF data with effective undersampling factor of 3 in the slice direction were acquired with quadratic RF phase patterns for T1 , T2 , and T 2 ∗ sensitivity. Quadratic RF phase encodes the off-resonance by modulating the on-resonance frequency linearly in time. Transition to 3D brings practical limitations for reconstruction and dictionary matching because of increased data and dictionary sizes. Randomized singular value decomposition (rSVD)-based compression in time and reduction in dictionary size with a quadratic interpolation method are combined to be able to process prohibitively large data sets in feasible reconstruction and matching times. RESULTS Accuracy of 3D qRF-MRF maps in various resolutions and orientations are compared to 3D fast imaging with steady-state precession (FISP) for T1 and T2 contrast and to 2D qRF-MRF for T 2 ∗ contrast and ΔB0 . The precision of 3D qRF-MRF was 1.5-2 times higher than routine clinical scans. 3D qRF-MRF ΔB0 maps were further processed to highlight the susceptibility contrast. CONCLUSION Natively co-registered 3D whole brain T1 , T2 , T 2 ∗ , ΔB0 , and QSM maps can be acquired in as short as 5 min with 3D qRF-MRF.
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Affiliation(s)
- Rasim Boyacioglu
- Department of Radiology, Case Western Reserve University, Cleveland, Ohio, USA
| | - Charlie Wang
- Department of Radiology, Case Western Reserve University, Cleveland, Ohio, USA
| | - Dan Ma
- Department of Radiology, Case Western Reserve University, Cleveland, Ohio, USA
| | - Debra F McGivney
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio, USA
| | - Xin Yu
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio, USA
| | - Mark A Griswold
- Department of Radiology, Case Western Reserve University, Cleveland, Ohio, USA
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18
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Accelerating quantitative MR imaging with the incorporation of B1 compensation using deep learning. Magn Reson Imaging 2020; 72:78-86. [DOI: 10.1016/j.mri.2020.06.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 05/20/2020] [Accepted: 06/13/2020] [Indexed: 11/21/2022]
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19
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McGivney DF, Boyacioğlu R, Jiang Y, Poorman ME, Seiberlich N, Gulani V, Keenan KE, Griswold MA, Ma D. Magnetic resonance fingerprinting review part 2: Technique and directions. J Magn Reson Imaging 2020; 51:993-1007. [PMID: 31347226 PMCID: PMC6980890 DOI: 10.1002/jmri.26877] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 07/05/2019] [Accepted: 07/05/2019] [Indexed: 12/12/2022] Open
Abstract
Magnetic resonance fingerprinting (MRF) is a general framework to quantify multiple MR-sensitive tissue properties with a single acquisition. There have been numerous advances in MRF in the years since its inception. In this work we highlight some of the recent technical developments in MRF, focusing on sequence optimization, modifications for reconstruction and pattern matching, new methods for partial volume analysis, and applications of machine and deep learning. Level of Evidence: 2 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2020;51:993-1007.
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Affiliation(s)
- Debra F. McGivney
- Department of Radiology, Case Western Reserve University, Cleveland, Ohio, USA
| | - Rasim Boyacioğlu
- Department of Radiology, Case Western Reserve University, Cleveland, Ohio, USA
| | - Yun Jiang
- Department of Radiology, Case Western Reserve University, Cleveland, Ohio, USA
- Department of Radiology, University of Michigan, Ann Arbor, Michigan, USA
| | - Megan E. Poorman
- Department of Physics, University of Colorado Boulder, Boulder, Colorado, USA
- Physical Measurement Laboratory, National Institute of Standards and Technology, Boulder, Colorado, USA
| | - Nicole Seiberlich
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio, USA
- Department of Radiology, University of Michigan, Ann Arbor, Michigan, USA
| | - Vikas Gulani
- Department of Radiology, Case Western Reserve University, Cleveland, Ohio, USA
- Department of Radiology, University of Michigan, Ann Arbor, Michigan, USA
| | - Kathryn E. Keenan
- Physical Measurement Laboratory, National Institute of Standards and Technology, Boulder, Colorado, USA
| | - Mark A. Griswold
- Department of Radiology, Case Western Reserve University, Cleveland, Ohio, USA
| | - Dan Ma
- Department of Radiology, Case Western Reserve University, Cleveland, Ohio, USA
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20
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Lu L, Chen Y, Shen C, Lian J, Das S, Marks L, Lin W, Zhu T. Initial assessment of 3D magnetic resonance fingerprinting (MRF) towards quantitative brain imaging for radiation therapy. Med Phys 2019; 47:1199-1214. [PMID: 31834641 DOI: 10.1002/mp.13967] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 12/02/2019] [Accepted: 12/06/2019] [Indexed: 12/17/2022] Open
Abstract
PURPOSE Magnetic resonance fingerprinting (MRF) provides quantitative T1/T2 maps, enabling applications in clinical radiotherapy such as large-scale, multi-center clinical trials for longitudinal assessment of therapy response. We evaluated the feasibility of a quantitative three-dimensional-MRF (3D-MRF) towards its radiotherapy applications of primary brain tumors. METHODS A fast whole-brain 3D-MRF sequence initially developed for diagnostic radiology was optimized using flexible body coils, which is the typical MR imaging setup for radiotherapy treatment planning and for MR imaging (MRI)-guided treatment delivery. Optimization criteria included the accuracy and the precision of T1/T2 quantifications of polyvinylpyrrolidone (PVP) solutions, compared to those from the 3D-MRF using a 32-channel head coil. The accuracy of T1/T2 quantifications from the optimized MRF was first examined in healthy volunteers with two different coil setups. The intra- and inter-scanner variations of image intensity from the optimized sequence were quantified by longitudinal scans of the PVP solutions on two 3T scanners. Using a 3D-printed MRI geometry phantom, susceptibility-induced distortion with the optimized 3D-MRF was quantified as the Dice coefficient of phantom contours, compared to those from CT images. By introducing intentional head motion during 10% of the scan, the robustness of the optimized 3D-MRF towards motion was evaluated through visual inspection of motion artifacts and through quantitative analysis of image sharpness in brain MRF maps. RESULTS The optimized sequence acquired whole-brain T1, T2 and proton density maps and with a resolution of 1.2 × 1.2 × 3 mm3 in 10 min, similar to the total acquisition time of 3D T1- and T2-weighted images of the same resolution. In vivo T1 and T2 values of the white and gray matter were consistent with literature. The intra- and inter-scanner variability of the intensity-normalized MRF T1 was 1.0% ± 0.7% and 2.3% ± 1.0% respectively, in contrast to 5.3% ± 3.8% and 3.2% ± 1.6% from the normalized T1-weighted MRI. Repeatability and reproducibility of MRF T1 were independent of intensity normalization. Both phantom and human data demonstrated that the optimized 3D-MRF is more robust to subject motion and artifacts from subject-specific susceptibility difference. Compared to CT contours, the Dice coefficient of phantom contours from 3D-MRF was 0.93, improved from 0.87 from the T1-weighted MRI. CONCLUSION Compared to conventional MRI, the optimized 3D-MRF demonstrated improved repeatability across time points and reproducibility across scanners for better tissue quantification, as well as improved robustness to subject-specific susceptibility and motion artifacts under a typical MR imaging setup for radiotherapy. More importantly, quantitative MRF T1/T2 measurements lead to promising potentials towards longitudinal quantitative assessment of treatment response for better adaptive therapy and for large-scale, multi-center clinical trials.
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Affiliation(s)
- Lan Lu
- Department of Radiation Oncology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Yong Chen
- Department of Radiology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.,Biomedical Research Imaging Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Colette Shen
- Department of Radiation Oncology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Jun Lian
- Department of Radiation Oncology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Shiva Das
- Department of Radiation Oncology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Lawrence Marks
- Department of Radiation Oncology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Weili Lin
- Department of Radiology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.,Biomedical Research Imaging Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Tong Zhu
- Department of Radiation Oncology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
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21
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Lee PK, Watkins LE, Anderson TI, Buonincontri G, Hargreaves BA. Flexible and efficient optimization of quantitative sequences using automatic differentiation of Bloch simulations. Magn Reson Med 2019; 82:1438-1451. [PMID: 31131500 PMCID: PMC8057531 DOI: 10.1002/mrm.27832] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Revised: 05/06/2019] [Accepted: 05/08/2019] [Indexed: 12/21/2022]
Abstract
PURPOSE To investigate a computationally efficient method for optimizing the Cramér-Rao Lower Bound (CRLB) of quantitative sequences without using approximations or an analytical expression of the signal. METHODS Automatic differentiation was applied to Bloch simulations and used to optimize several quantitative sequences without the need for approximations or an analytical expression. The results were validated with in vivo measurements and comparisons to prior art. Multi-echo spin echo and DESPO T 1 were used as benchmarks to verify the CRLB implementation. The CRLB of the Magnetic Resonance Fingerprinting (MRF) sequence, which has a complicated analytical formulation, was also optimized using automatic differentiation. RESULTS The sequence parameters obtained for multi-echo spin echo and DESPO T 1 matched results obtained using conventional methods. In vivo, MRF scans demonstrate that the CRLB optimization obtained with automatic differentiation can improve performance in presence of white noise. For MRF, the CRLB optimization converges in 1.1 CPU hours for N TR = 400 and has O ( N TR ) asymptotic runtime scaling for the calculation of the CRLB objective and gradient. CONCLUSIONS Automatic differentiation can be used to optimize the CRLB of quantitative sequences without using approximations or analytical expressions. For MRF, the runtime is computationally efficient and can be used to investigate confounding factors as well as MRF sequences with a greater number of repetitions.
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Affiliation(s)
- Philip K. Lee
- Radiology, Stanford University, Stanford, CA, 94305, USA
- Electrical Engineering, Stanford University, Stanford, CA, 94305, USA
| | - Lauren E. Watkins
- Radiology, Stanford University, Stanford, CA, 94305, USA
- Bioengineering, Stanford University, Stanford, CA, 94305, USA
| | | | - Guido Buonincontri
- IRCCS Fondazione Stella Maris, Pisa, PI, 56128, Italy
- Fondazione Imago7, Pisa, PI, 56128, Italy
| | - Brian A. Hargreaves
- Radiology, Stanford University, Stanford, CA, 94305, USA
- Electrical Engineering, Stanford University, Stanford, CA, 94305, USA
- Bioengineering, Stanford University, Stanford, CA, 94305, USA
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22
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Poorman ME, Martin MN, Ma D, McGivney DF, Gulani V, Griswold MA, Keenan KE. Magnetic resonance fingerprinting Part 1: Potential uses, current challenges, and recommendations. J Magn Reson Imaging 2019; 51:675-692. [PMID: 31264748 DOI: 10.1002/jmri.26836] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2019] [Accepted: 05/31/2019] [Indexed: 12/11/2022] Open
Abstract
Magnetic resonance fingerprinting (MRF) is a powerful quantitative MRI technique capable of acquiring multiple property maps simultaneously in a short timeframe. The MRF framework has been adapted to a wide variety of clinical applications, but faces challenges in technical development, and to date has only demonstrated repeatability and reproducibility in small studies. In this review, we discuss the current implementations of MRF and their use in a clinical setting. Based on this analysis, we highlight areas of need that must be addressed before MRF can be fully adopted into the clinic and make recommendations to the MRF community on standardization and validation strategies of MRF techniques. Level of Evidence: 2 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2020;51:675-692.
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Affiliation(s)
- Megan E. Poorman
- Department of PhysicsUniversity of Colorado Boulder Boulder Colorado USA
- Physical Measurement LaboratoryNational Institute of Standards and Technology Boulder Colorado USA
| | - Michele N. Martin
- Physical Measurement LaboratoryNational Institute of Standards and Technology Boulder Colorado USA
| | - Dan Ma
- Department of RadiologyCase Western Reserve University Cleveland Ohio USA
| | - Debra F. McGivney
- Department of RadiologyCase Western Reserve University Cleveland Ohio USA
| | - Vikas Gulani
- Department of RadiologyCase Western Reserve University Cleveland Ohio USA
| | - Mark A. Griswold
- Department of RadiologyCase Western Reserve University Cleveland Ohio USA
| | - Kathryn E. Keenan
- Physical Measurement LaboratoryNational Institute of Standards and Technology Boulder Colorado USA
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23
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Kato Y, Ichikawa K, Okudaira K, Taoka T, Kawaguchi H, Murata K, Maruyama K, Koerzdoerfer G, Pfeuffer J, Nittka M, Naganawa S. Comprehensive Evaluation of B 1+-corrected FISP-based Magnetic Resonance Fingerprinting: Accuracy, Repeatability and Reproducibility of T 1 and T 2 Relaxation Times for ISMRM/NIST System Phantom and Volunteers. Magn Reson Med Sci 2019; 19:168-175. [PMID: 31217366 PMCID: PMC7553811 DOI: 10.2463/mrms.mp.2019-0016] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Purpose: This study aimed to evaluate comprehensively; accuracy, repeatability and reproducibility of T1 and T2 relaxation times measured by magnetic resonance fingerprinting using B1+-corrected fast imaging with steady-state precession (FISP–MRF). Methods: The International Society of Magnetic Resonance in Medicine/National Institute of Standards and Technology (ISMRM/NIST) phantom was scanned for 100 days, and six healthy volunteers for 5 days using a FISP–MRF prototype sequence. Accuracy was evaluated on the phantom by comparing relaxation times measured by FISP–MRF with the reference values provided by the phantom manufacturer. Daily repeatability was characterized as the coefficient of variation (CV) of the measurements over 100 days for the phantom and over 5 days for volunteers. In addition, the cross-scanner reproducibility was evaluated in volunteers. Results: In the phantom study, T1 and T2 values from FISP–MRF showed a strong linear correlation with the reference values of the phantom (R2 = 0.9963 for T1; R2 = 0.9966 for T2). CVs were <1.0% for T1 values larger than 300 ms, and <3.0% for T2 values across a wide range. In the volunteer study, CVs for both T1 and T2 values were <5.0%, except for one subject. In addition, all T2 values estimated by FISP–MRF in vivo were lower than those measured with conventional mapping sequences reported in previous studies. The cross-scanner variation of T1 and T2 showed good agreement between two different scanners in the volunteers. Conclusion: B1+-corrected FISP-MRF showed an acceptable accuracy, repeatability and reproducibility in the phantom and volunteer studies.
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Affiliation(s)
- Yutaka Kato
- Department of Radiological Technology, Nagoya University Hospital
| | | | | | - Toshiaki Taoka
- Department of Radiology, Graduate School of Medicine, Nagoya University
| | | | | | | | | | | | | | - Shinji Naganawa
- Department of Radiology, Graduate School of Medicine, Nagoya University
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24
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Körzdörfer G, Kirsch R, Liu K, Pfeuffer J, Hensel B, Jiang Y, Ma D, Gratz M, Bär P, Bogner W, Springer E, Lima Cardoso P, Umutlu L, Trattnig S, Griswold M, Gulani V, Nittka M. Reproducibility and Repeatability of MR Fingerprinting Relaxometry in the Human Brain. Radiology 2019; 292:429-437. [PMID: 31210615 DOI: 10.1148/radiol.2019182360] [Citation(s) in RCA: 71] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Background Only sparse literature investigates the reproducibility and repeatability of relaxometry methods in MRI. However, statistical data on reproducibility and repeatability of any quantitative method is essential for clinical application. Purpose To evaluate the reproducibility and repeatability of two-dimensional fast imaging with steady-state free precession MR fingerprinting in vivo in human brains. Materials and Methods Two-dimensional section-selective MR fingerprinting based on a steady-state free precession sequence with an external radiofrequency transmit field, or B1+, correction was used to generate T1 and T2 maps. This prospective study was conducted between July 2017 and January 2018 with 10 scanners from a single manufacturer, including different models, at four different sites. T1 and T2 relaxation times and their variation across scanners (reproducibility) as well as across repetitions on a scanner (repeatability) were analyzed. The relative deviations of T1 and T2 to the average (95% confidence interval) were calculated for several brain compartments. Results Ten healthy volunteers (mean age ± standard deviation, 28.5 years ± 6.9; eight men, two women) participated in this study. Reproducibility and repeatability of T1 and T2 measures in the human brain varied across brain compartments (1.8%-20.9%) and were higher in solid tissues than in the cerebrospinal fluid. T1 measures in solid tissue brain compartments were more stable compared with T2 measures. The half-widths of the confidence intervals for relative deviations were 3.4% for mean T1 and 8.0% for mean T2 values across scanners. Intrascanner repeatability half-widths of the confidence intervals for relative deviations were in the range of 2.0%-3.1% for T1 and 3.1%-7.9% for T2. Conclusion This study provides values on reproducibility and repeatability of T1 and T2 relaxometry measured with fast imaging with steady-state free precession MR fingerprinting in brain tissues of healthy volunteers. Reproducibility and repeatability are considerably higher in solid brain compartments than in cerebrospinal fluid and are higher for T1 than for T2. © RSNA, 2019 Online supplemental material is available for this article. See also the editorial by Barkhof and Parker in this issue.
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Affiliation(s)
- Gregor Körzdörfer
- From Siemens Healthcare, Allee am Roethelheimpark 2, 91052 Erlangen, Germany (G.K., R.K., J.P., M.N.); Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany (G.K., B.H.); Siemens Medical Solutions USA, Malvern, Pa (K.L.); Departments of Biomedical Engineering (Y.J., D.M., M. Griswold, V.G.) and Radiology (M. Griswold, V.G.), Case Western Reserve University, Cleveland, Ohio; Department of High Field and Hybrid MR Imaging, University Hospital Essen, Essen, Germany (M. Gratz); Erwin L. Hahn Institute for MRI, University Duisburg-Essen, Essen, Germany (M. Gratz); Department of Biomedical Imaging and Image-guided Therapy, High Field Magnetic Resonance Center, Medical University of Vienna, Vienna, Austria (P.B., W.B., E.S., P.L.C., S.T.); Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, Germany (L.U.); and Christian Doppler Laboratory for Clinical Molecular MR Imaging, MOLIMA, Vienna, Austria (W.B., S.T.)
| | - Rainer Kirsch
- From Siemens Healthcare, Allee am Roethelheimpark 2, 91052 Erlangen, Germany (G.K., R.K., J.P., M.N.); Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany (G.K., B.H.); Siemens Medical Solutions USA, Malvern, Pa (K.L.); Departments of Biomedical Engineering (Y.J., D.M., M. Griswold, V.G.) and Radiology (M. Griswold, V.G.), Case Western Reserve University, Cleveland, Ohio; Department of High Field and Hybrid MR Imaging, University Hospital Essen, Essen, Germany (M. Gratz); Erwin L. Hahn Institute for MRI, University Duisburg-Essen, Essen, Germany (M. Gratz); Department of Biomedical Imaging and Image-guided Therapy, High Field Magnetic Resonance Center, Medical University of Vienna, Vienna, Austria (P.B., W.B., E.S., P.L.C., S.T.); Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, Germany (L.U.); and Christian Doppler Laboratory for Clinical Molecular MR Imaging, MOLIMA, Vienna, Austria (W.B., S.T.)
| | - Kecheng Liu
- From Siemens Healthcare, Allee am Roethelheimpark 2, 91052 Erlangen, Germany (G.K., R.K., J.P., M.N.); Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany (G.K., B.H.); Siemens Medical Solutions USA, Malvern, Pa (K.L.); Departments of Biomedical Engineering (Y.J., D.M., M. Griswold, V.G.) and Radiology (M. Griswold, V.G.), Case Western Reserve University, Cleveland, Ohio; Department of High Field and Hybrid MR Imaging, University Hospital Essen, Essen, Germany (M. Gratz); Erwin L. Hahn Institute for MRI, University Duisburg-Essen, Essen, Germany (M. Gratz); Department of Biomedical Imaging and Image-guided Therapy, High Field Magnetic Resonance Center, Medical University of Vienna, Vienna, Austria (P.B., W.B., E.S., P.L.C., S.T.); Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, Germany (L.U.); and Christian Doppler Laboratory for Clinical Molecular MR Imaging, MOLIMA, Vienna, Austria (W.B., S.T.)
| | - Josef Pfeuffer
- From Siemens Healthcare, Allee am Roethelheimpark 2, 91052 Erlangen, Germany (G.K., R.K., J.P., M.N.); Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany (G.K., B.H.); Siemens Medical Solutions USA, Malvern, Pa (K.L.); Departments of Biomedical Engineering (Y.J., D.M., M. Griswold, V.G.) and Radiology (M. Griswold, V.G.), Case Western Reserve University, Cleveland, Ohio; Department of High Field and Hybrid MR Imaging, University Hospital Essen, Essen, Germany (M. Gratz); Erwin L. Hahn Institute for MRI, University Duisburg-Essen, Essen, Germany (M. Gratz); Department of Biomedical Imaging and Image-guided Therapy, High Field Magnetic Resonance Center, Medical University of Vienna, Vienna, Austria (P.B., W.B., E.S., P.L.C., S.T.); Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, Germany (L.U.); and Christian Doppler Laboratory for Clinical Molecular MR Imaging, MOLIMA, Vienna, Austria (W.B., S.T.)
| | - Bernhard Hensel
- From Siemens Healthcare, Allee am Roethelheimpark 2, 91052 Erlangen, Germany (G.K., R.K., J.P., M.N.); Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany (G.K., B.H.); Siemens Medical Solutions USA, Malvern, Pa (K.L.); Departments of Biomedical Engineering (Y.J., D.M., M. Griswold, V.G.) and Radiology (M. Griswold, V.G.), Case Western Reserve University, Cleveland, Ohio; Department of High Field and Hybrid MR Imaging, University Hospital Essen, Essen, Germany (M. Gratz); Erwin L. Hahn Institute for MRI, University Duisburg-Essen, Essen, Germany (M. Gratz); Department of Biomedical Imaging and Image-guided Therapy, High Field Magnetic Resonance Center, Medical University of Vienna, Vienna, Austria (P.B., W.B., E.S., P.L.C., S.T.); Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, Germany (L.U.); and Christian Doppler Laboratory for Clinical Molecular MR Imaging, MOLIMA, Vienna, Austria (W.B., S.T.)
| | - Yun Jiang
- From Siemens Healthcare, Allee am Roethelheimpark 2, 91052 Erlangen, Germany (G.K., R.K., J.P., M.N.); Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany (G.K., B.H.); Siemens Medical Solutions USA, Malvern, Pa (K.L.); Departments of Biomedical Engineering (Y.J., D.M., M. Griswold, V.G.) and Radiology (M. Griswold, V.G.), Case Western Reserve University, Cleveland, Ohio; Department of High Field and Hybrid MR Imaging, University Hospital Essen, Essen, Germany (M. Gratz); Erwin L. Hahn Institute for MRI, University Duisburg-Essen, Essen, Germany (M. Gratz); Department of Biomedical Imaging and Image-guided Therapy, High Field Magnetic Resonance Center, Medical University of Vienna, Vienna, Austria (P.B., W.B., E.S., P.L.C., S.T.); Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, Germany (L.U.); and Christian Doppler Laboratory for Clinical Molecular MR Imaging, MOLIMA, Vienna, Austria (W.B., S.T.)
| | - Dan Ma
- From Siemens Healthcare, Allee am Roethelheimpark 2, 91052 Erlangen, Germany (G.K., R.K., J.P., M.N.); Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany (G.K., B.H.); Siemens Medical Solutions USA, Malvern, Pa (K.L.); Departments of Biomedical Engineering (Y.J., D.M., M. Griswold, V.G.) and Radiology (M. Griswold, V.G.), Case Western Reserve University, Cleveland, Ohio; Department of High Field and Hybrid MR Imaging, University Hospital Essen, Essen, Germany (M. Gratz); Erwin L. Hahn Institute for MRI, University Duisburg-Essen, Essen, Germany (M. Gratz); Department of Biomedical Imaging and Image-guided Therapy, High Field Magnetic Resonance Center, Medical University of Vienna, Vienna, Austria (P.B., W.B., E.S., P.L.C., S.T.); Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, Germany (L.U.); and Christian Doppler Laboratory for Clinical Molecular MR Imaging, MOLIMA, Vienna, Austria (W.B., S.T.)
| | - Marcel Gratz
- From Siemens Healthcare, Allee am Roethelheimpark 2, 91052 Erlangen, Germany (G.K., R.K., J.P., M.N.); Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany (G.K., B.H.); Siemens Medical Solutions USA, Malvern, Pa (K.L.); Departments of Biomedical Engineering (Y.J., D.M., M. Griswold, V.G.) and Radiology (M. Griswold, V.G.), Case Western Reserve University, Cleveland, Ohio; Department of High Field and Hybrid MR Imaging, University Hospital Essen, Essen, Germany (M. Gratz); Erwin L. Hahn Institute for MRI, University Duisburg-Essen, Essen, Germany (M. Gratz); Department of Biomedical Imaging and Image-guided Therapy, High Field Magnetic Resonance Center, Medical University of Vienna, Vienna, Austria (P.B., W.B., E.S., P.L.C., S.T.); Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, Germany (L.U.); and Christian Doppler Laboratory for Clinical Molecular MR Imaging, MOLIMA, Vienna, Austria (W.B., S.T.)
| | - Peter Bär
- From Siemens Healthcare, Allee am Roethelheimpark 2, 91052 Erlangen, Germany (G.K., R.K., J.P., M.N.); Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany (G.K., B.H.); Siemens Medical Solutions USA, Malvern, Pa (K.L.); Departments of Biomedical Engineering (Y.J., D.M., M. Griswold, V.G.) and Radiology (M. Griswold, V.G.), Case Western Reserve University, Cleveland, Ohio; Department of High Field and Hybrid MR Imaging, University Hospital Essen, Essen, Germany (M. Gratz); Erwin L. Hahn Institute for MRI, University Duisburg-Essen, Essen, Germany (M. Gratz); Department of Biomedical Imaging and Image-guided Therapy, High Field Magnetic Resonance Center, Medical University of Vienna, Vienna, Austria (P.B., W.B., E.S., P.L.C., S.T.); Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, Germany (L.U.); and Christian Doppler Laboratory for Clinical Molecular MR Imaging, MOLIMA, Vienna, Austria (W.B., S.T.)
| | - Wolfgang Bogner
- From Siemens Healthcare, Allee am Roethelheimpark 2, 91052 Erlangen, Germany (G.K., R.K., J.P., M.N.); Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany (G.K., B.H.); Siemens Medical Solutions USA, Malvern, Pa (K.L.); Departments of Biomedical Engineering (Y.J., D.M., M. Griswold, V.G.) and Radiology (M. Griswold, V.G.), Case Western Reserve University, Cleveland, Ohio; Department of High Field and Hybrid MR Imaging, University Hospital Essen, Essen, Germany (M. Gratz); Erwin L. Hahn Institute for MRI, University Duisburg-Essen, Essen, Germany (M. Gratz); Department of Biomedical Imaging and Image-guided Therapy, High Field Magnetic Resonance Center, Medical University of Vienna, Vienna, Austria (P.B., W.B., E.S., P.L.C., S.T.); Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, Germany (L.U.); and Christian Doppler Laboratory for Clinical Molecular MR Imaging, MOLIMA, Vienna, Austria (W.B., S.T.)
| | - Elisabeth Springer
- From Siemens Healthcare, Allee am Roethelheimpark 2, 91052 Erlangen, Germany (G.K., R.K., J.P., M.N.); Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany (G.K., B.H.); Siemens Medical Solutions USA, Malvern, Pa (K.L.); Departments of Biomedical Engineering (Y.J., D.M., M. Griswold, V.G.) and Radiology (M. Griswold, V.G.), Case Western Reserve University, Cleveland, Ohio; Department of High Field and Hybrid MR Imaging, University Hospital Essen, Essen, Germany (M. Gratz); Erwin L. Hahn Institute for MRI, University Duisburg-Essen, Essen, Germany (M. Gratz); Department of Biomedical Imaging and Image-guided Therapy, High Field Magnetic Resonance Center, Medical University of Vienna, Vienna, Austria (P.B., W.B., E.S., P.L.C., S.T.); Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, Germany (L.U.); and Christian Doppler Laboratory for Clinical Molecular MR Imaging, MOLIMA, Vienna, Austria (W.B., S.T.)
| | - Pedro Lima Cardoso
- From Siemens Healthcare, Allee am Roethelheimpark 2, 91052 Erlangen, Germany (G.K., R.K., J.P., M.N.); Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany (G.K., B.H.); Siemens Medical Solutions USA, Malvern, Pa (K.L.); Departments of Biomedical Engineering (Y.J., D.M., M. Griswold, V.G.) and Radiology (M. Griswold, V.G.), Case Western Reserve University, Cleveland, Ohio; Department of High Field and Hybrid MR Imaging, University Hospital Essen, Essen, Germany (M. Gratz); Erwin L. Hahn Institute for MRI, University Duisburg-Essen, Essen, Germany (M. Gratz); Department of Biomedical Imaging and Image-guided Therapy, High Field Magnetic Resonance Center, Medical University of Vienna, Vienna, Austria (P.B., W.B., E.S., P.L.C., S.T.); Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, Germany (L.U.); and Christian Doppler Laboratory for Clinical Molecular MR Imaging, MOLIMA, Vienna, Austria (W.B., S.T.)
| | - Lale Umutlu
- From Siemens Healthcare, Allee am Roethelheimpark 2, 91052 Erlangen, Germany (G.K., R.K., J.P., M.N.); Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany (G.K., B.H.); Siemens Medical Solutions USA, Malvern, Pa (K.L.); Departments of Biomedical Engineering (Y.J., D.M., M. Griswold, V.G.) and Radiology (M. Griswold, V.G.), Case Western Reserve University, Cleveland, Ohio; Department of High Field and Hybrid MR Imaging, University Hospital Essen, Essen, Germany (M. Gratz); Erwin L. Hahn Institute for MRI, University Duisburg-Essen, Essen, Germany (M. Gratz); Department of Biomedical Imaging and Image-guided Therapy, High Field Magnetic Resonance Center, Medical University of Vienna, Vienna, Austria (P.B., W.B., E.S., P.L.C., S.T.); Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, Germany (L.U.); and Christian Doppler Laboratory for Clinical Molecular MR Imaging, MOLIMA, Vienna, Austria (W.B., S.T.)
| | - Siegfried Trattnig
- From Siemens Healthcare, Allee am Roethelheimpark 2, 91052 Erlangen, Germany (G.K., R.K., J.P., M.N.); Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany (G.K., B.H.); Siemens Medical Solutions USA, Malvern, Pa (K.L.); Departments of Biomedical Engineering (Y.J., D.M., M. Griswold, V.G.) and Radiology (M. Griswold, V.G.), Case Western Reserve University, Cleveland, Ohio; Department of High Field and Hybrid MR Imaging, University Hospital Essen, Essen, Germany (M. Gratz); Erwin L. Hahn Institute for MRI, University Duisburg-Essen, Essen, Germany (M. Gratz); Department of Biomedical Imaging and Image-guided Therapy, High Field Magnetic Resonance Center, Medical University of Vienna, Vienna, Austria (P.B., W.B., E.S., P.L.C., S.T.); Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, Germany (L.U.); and Christian Doppler Laboratory for Clinical Molecular MR Imaging, MOLIMA, Vienna, Austria (W.B., S.T.)
| | - Mark Griswold
- From Siemens Healthcare, Allee am Roethelheimpark 2, 91052 Erlangen, Germany (G.K., R.K., J.P., M.N.); Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany (G.K., B.H.); Siemens Medical Solutions USA, Malvern, Pa (K.L.); Departments of Biomedical Engineering (Y.J., D.M., M. Griswold, V.G.) and Radiology (M. Griswold, V.G.), Case Western Reserve University, Cleveland, Ohio; Department of High Field and Hybrid MR Imaging, University Hospital Essen, Essen, Germany (M. Gratz); Erwin L. Hahn Institute for MRI, University Duisburg-Essen, Essen, Germany (M. Gratz); Department of Biomedical Imaging and Image-guided Therapy, High Field Magnetic Resonance Center, Medical University of Vienna, Vienna, Austria (P.B., W.B., E.S., P.L.C., S.T.); Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, Germany (L.U.); and Christian Doppler Laboratory for Clinical Molecular MR Imaging, MOLIMA, Vienna, Austria (W.B., S.T.)
| | - Vikas Gulani
- From Siemens Healthcare, Allee am Roethelheimpark 2, 91052 Erlangen, Germany (G.K., R.K., J.P., M.N.); Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany (G.K., B.H.); Siemens Medical Solutions USA, Malvern, Pa (K.L.); Departments of Biomedical Engineering (Y.J., D.M., M. Griswold, V.G.) and Radiology (M. Griswold, V.G.), Case Western Reserve University, Cleveland, Ohio; Department of High Field and Hybrid MR Imaging, University Hospital Essen, Essen, Germany (M. Gratz); Erwin L. Hahn Institute for MRI, University Duisburg-Essen, Essen, Germany (M. Gratz); Department of Biomedical Imaging and Image-guided Therapy, High Field Magnetic Resonance Center, Medical University of Vienna, Vienna, Austria (P.B., W.B., E.S., P.L.C., S.T.); Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, Germany (L.U.); and Christian Doppler Laboratory for Clinical Molecular MR Imaging, MOLIMA, Vienna, Austria (W.B., S.T.)
| | - Mathias Nittka
- From Siemens Healthcare, Allee am Roethelheimpark 2, 91052 Erlangen, Germany (G.K., R.K., J.P., M.N.); Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany (G.K., B.H.); Siemens Medical Solutions USA, Malvern, Pa (K.L.); Departments of Biomedical Engineering (Y.J., D.M., M. Griswold, V.G.) and Radiology (M. Griswold, V.G.), Case Western Reserve University, Cleveland, Ohio; Department of High Field and Hybrid MR Imaging, University Hospital Essen, Essen, Germany (M. Gratz); Erwin L. Hahn Institute for MRI, University Duisburg-Essen, Essen, Germany (M. Gratz); Department of Biomedical Imaging and Image-guided Therapy, High Field Magnetic Resonance Center, Medical University of Vienna, Vienna, Austria (P.B., W.B., E.S., P.L.C., S.T.); Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, Germany (L.U.); and Christian Doppler Laboratory for Clinical Molecular MR Imaging, MOLIMA, Vienna, Austria (W.B., S.T.)
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