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Bontempi P, Rozzanigo U, Marangoni S, Fogazzi E, Ravanelli D, Cazzoletti L, Giometto B, Farace P. Non-lesional white matter in relapsing-remitting multiple sclerosis assessed by multicomponent T2 relaxation. Brain Behav 2023; 13:e3334. [PMID: 38041516 PMCID: PMC10726908 DOI: 10.1002/brb3.3334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 10/31/2023] [Accepted: 11/02/2023] [Indexed: 12/03/2023] Open
Abstract
INTRODUCTION The purpose of the study is to investigate, by T2 relaxation, non-lesional white matter (WM) in relapsing-remitting (RR) multiple sclerosis (MS). METHODS Twenty stable RR MS patients underwent 1.5T Magnetic Resonance Imaging (MRI) with 3D Fluid-Attenuated Inversion-Recovery (FLAIR), 3D-T1-weighted, and T2-relaxation multi-echo sequences. The Lesion Segmentation Tool processed FLAIR images to identify focal lesions (FLs), whereas T1 images were segmented to identify WM and FL sub-volumes with T1 hypo-intensity. Non-lesional WM was obtained as the segmented WM, excluding FL volumes. The multi-echo sequence allowed decomposition into myelin water, intra-extracellular water, and free water (Fw), which were evaluated on the segmented non-lesional WM. Correlation analysis was performed between the non-lesional WM relaxation parameters and Expanded Disability Status Scale (EDSS), disease duration, patient age, and T1 hypo-intense FL volumes. RESULTS The T1 hypo-intense FL volumes correlated with EDSS. On the non-lesional WM, the median Fw correlated with EDSS, disease duration, age, and T1 hypo-intense FL volumes. Bivariate EDSS correlation of FL volumes and WM T2-relaxation parameters did not improve significance. CONCLUSION T2 relaxation allowed identifying subtle WM alterations, which significantly correlated with EDSS, disease duration, and age but do not seem to be EDSS-predictors independent from FL sub-volumes in stable RR patients. Particularly, the increase in the Fw component is suggestive of an uninvestigated prodromal phenomenon in brain degeneration.
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Affiliation(s)
- Pietro Bontempi
- Department of Engineering for Innovation MedicineUniversity of VeronaVeronaItaly
| | - Umberto Rozzanigo
- Neuro‐radiology Unit, Hospital of TrentoAzienda Provinciale per i Servizi Sanitari (APSS)TrentoItaly
| | - Sabrina Marangoni
- Neurology Unit, Hospital of TrentoAzienda Provinciale per i Servizi Sanitari (APSS)TrentoItaly
| | - Elena Fogazzi
- Physics departmentUniversity of TrentoPovoTrentoItaly
| | - Daniele Ravanelli
- Medical Physics Department, Hospital of TrentoAzienda Provinciale per i Servizi Sanitari (APSS)TrentoItaly
| | - Lucia Cazzoletti
- Unit of Epidemiology and Medical Statistics, Department of Diagnostics and Public HealthUniversity of VeronaVeronaItaly
| | - Bruno Giometto
- Neurology Unit, Hospital of TrentoAzienda Provinciale per i Servizi Sanitari (APSS)TrentoItaly
| | - Paolo Farace
- Medical Physics Department, Hospital of TrentoAzienda Provinciale per i Servizi Sanitari (APSS)TrentoItaly
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Zhang S, She S, Qiu Y, Li Z, Mao D, Zheng W, Wu H, Huang R. Altered cortical myelin in the salience and default mode networks in major depressive disorder patients: A surface-based analysis. J Affect Disord 2023; 340:113-119. [PMID: 37517634 DOI: 10.1016/j.jad.2023.07.068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 05/23/2023] [Accepted: 07/14/2023] [Indexed: 08/01/2023]
Abstract
INTRODUCTION Evidence from previous genetic and post-mortem studies suggested that the myelination abnormality contributed to the pathogenesis of major depressive disorder (MDD). However, image-level alterations in cortical myelin content associated with MDD are still unclear. METHODS The high-resolution T1-weighted (T1w) and T2-weighted (T2w) brain 3D structural images were obtained from 52 MDD patients and 52 healthy controls (HC). We calculated the vertex-based T1w/T2w ratio using the HCP structural pipelines to characterize individual cortical myelin maps at the fs_LR 32 k surface. We attempted to detect the clusters with significant differences in cortical myelin content between MDD and HC groups. We correlated the cluster-wise averaged myelin value and the clinical performances in MDD patients. RESULTS The MDD patients showed significantly lower cortical myelin content in the cluster involving the left insula, orbitofrontal cortex, superior temporal cortex, transverse temporal gyrus, inferior frontal cortex, superior frontal gyrus, anterior cingulate cortex, precentral cortex, and postcentral cortex. The correlation analysis showed a significantly positive correlation between the cluster-wise cortical myelin content and the onset age of MDD patients. CONCLUSION The MDD patients showed lower cortical myelin content in regions of the default mode network regions and salience network than healthy controls.
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Affiliation(s)
- Shufei Zhang
- School of Psychology, Center for the Study of Applied Psychology, Key Laboratory of Mental Health and Cognitive Science of Guangdong Province, Institute for Brain Research and Rehabilitation, South China Normal University, Guangzhou, 510631, China
| | - Shenglin She
- The Affiliated Brain Hospital of Guangzhou Medical University, Guangzhou, 510370, China; Guangdong Engineering Technology Research Center for Translational Medicine of Mental Disorders, Guangzhou, 510370, China
| | - Yidan Qiu
- School of Psychology, Center for the Study of Applied Psychology, Key Laboratory of Mental Health and Cognitive Science of Guangdong Province, Institute for Brain Research and Rehabilitation, South China Normal University, Guangzhou, 510631, China
| | - Zezhi Li
- School of Psychology, Center for the Study of Applied Psychology, Key Laboratory of Mental Health and Cognitive Science of Guangdong Province, Institute for Brain Research and Rehabilitation, South China Normal University, Guangzhou, 510631, China; The Affiliated Brain Hospital of Guangzhou Medical University, Guangzhou, 510370, China
| | - Deng Mao
- School of Psychology, Center for the Study of Applied Psychology, Key Laboratory of Mental Health and Cognitive Science of Guangdong Province, Institute for Brain Research and Rehabilitation, South China Normal University, Guangzhou, 510631, China
| | - Wei Zheng
- The Affiliated Brain Hospital of Guangzhou Medical University, Guangzhou, 510370, China; Guangdong Engineering Technology Research Center for Translational Medicine of Mental Disorders, Guangzhou, 510370, China
| | - Huawang Wu
- The Affiliated Brain Hospital of Guangzhou Medical University, Guangzhou, 510370, China; Guangdong Engineering Technology Research Center for Translational Medicine of Mental Disorders, Guangzhou, 510370, China.
| | - Ruiwang Huang
- School of Psychology, Center for the Study of Applied Psychology, Key Laboratory of Mental Health and Cognitive Science of Guangdong Province, Institute for Brain Research and Rehabilitation, South China Normal University, Guangzhou, 510631, China.
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Morris SR, Vavasour IM, Smolina A, MacMillan EL, Gilbert G, Lam M, Kozlowski P, Michal CA, Manning A, MacKay AL, Laule C. Myelin biomarkers in the healthy adult brain: Correlation, reproducibility, and the effect of fiber orientation. Magn Reson Med 2023; 89:1809-1824. [PMID: 36511247 DOI: 10.1002/mrm.29552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 10/17/2022] [Accepted: 11/18/2022] [Indexed: 12/15/2022]
Abstract
PURPOSE We investigated the correlation, reproducibility, and effect of white matter fiber orientation for three myelin-sensitive MRI techniques: magnetization transfer ratio (MTR), inhomogeneous magnetization transfer ratio (ihMTR), and gradient and spin echo-derived myelin water fraction (MWF). METHODS We measured the three metrics in 17 white and three deep grey matter regions in 17 healthy adults at 3 T. RESULTS We found a strong correlation between ihMTR and MTR (r = 0.70, p < 0.001) and ihMTR and MWF (r = 0.79, p < 0.001), and a weaker correlation between MTR and MWF (r = 0.54, p < 0.001). The dynamic range in white matter was greatest for MWF (2.0%-27.5%), followed by MTR (14.4%-23.2%) and then ihMTR (1.2%-5.4%). The average scan-rescan coefficient of variation for white matter regions was 0.6% MTR, 0.3% ihMTR, and 0.7% MWF in metric units; however, when adjusted by the dynamic range, these became 6.3%, 6.1% and 2.8%, respectively. All three metrics varied with fiber direction: MWF and ihMTR were lower in white matter fibers perpendicular to B0 by 6% and 1%, respectively, compared with those parallel, whereas MTR was lower by 0.5% at about 40°, with the highest values at 90°. However, separating the apparent orientation dependence by white matter region revealed large dissimilarities in the trends, suggesting that real differences in myelination between regions are confounding the apparent orientation dependence measured using this method. CONCLUSION The strong correlation between ihMTR and MWF suggests that these techniques are measuring the same myelination; however, the larger dynamic range of MWF may provide more power to detect small differences in myelin.
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Affiliation(s)
- Sarah R Morris
- Radiology, University of British Columbia, Vancouver, British Columbia, Canada.,Physics & Astronomy, University of British Columbia, Vancouver, British Columbia, Canada.,International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, British Columbia, Canada
| | - Irene M Vavasour
- Radiology, University of British Columbia, Vancouver, British Columbia, Canada.,International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, British Columbia, Canada.,UBC MRI Research Center, University of British Columbia, Vancouver, British Columbia, Canada
| | - Anastasia Smolina
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada.,The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Erin L MacMillan
- Radiology, University of British Columbia, Vancouver, British Columbia, Canada.,UBC MRI Research Center, University of British Columbia, Vancouver, British Columbia, Canada.,MR Clinical Science, Philips Healthcare Canada, Mississauga, Ontario, Canada
| | - Guillaume Gilbert
- MR Clinical Science, Philips Healthcare Canada, Mississauga, Ontario, Canada
| | - Michelle Lam
- Physics & Astronomy, University of British Columbia, Vancouver, British Columbia, Canada.,UBC MRI Research Center, University of British Columbia, Vancouver, British Columbia, Canada
| | - Piotr Kozlowski
- Radiology, University of British Columbia, Vancouver, British Columbia, Canada.,Physics & Astronomy, University of British Columbia, Vancouver, British Columbia, Canada.,International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, British Columbia, Canada.,UBC MRI Research Center, University of British Columbia, Vancouver, British Columbia, Canada
| | - Carl A Michal
- Physics & Astronomy, University of British Columbia, Vancouver, British Columbia, Canada
| | - Alan Manning
- Physics & Astronomy, University of British Columbia, Vancouver, British Columbia, Canada
| | - Alex L MacKay
- Radiology, University of British Columbia, Vancouver, British Columbia, Canada.,Physics & Astronomy, University of British Columbia, Vancouver, British Columbia, Canada.,UBC MRI Research Center, University of British Columbia, Vancouver, British Columbia, Canada
| | - Cornelia Laule
- Radiology, University of British Columbia, Vancouver, British Columbia, Canada.,Physics & Astronomy, University of British Columbia, Vancouver, British Columbia, Canada.,International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, British Columbia, Canada.,UBC MRI Research Center, University of British Columbia, Vancouver, British Columbia, Canada.,Pathology & Laboratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada
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4
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Kumar D, Benyard B, Soni ND, Swain A, Wilson N, Reddy R. Feasibility of transient nuclear Overhauser effect imaging in brain at 7 T. Magn Reson Med 2023; 89:1357-1367. [PMID: 36372994 DOI: 10.1002/mrm.29519] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Revised: 10/11/2022] [Accepted: 10/19/2022] [Indexed: 11/16/2022]
Abstract
PURPOSE The nuclear Overhauser effect (NOE) quantification from the steady-state NOE imaging suffers from multiple confounding non-NOE-specific sources, including direct saturation, magnetization transfer, and relevant chemical exchange species, and is affected by B0 and B1 + inhomogeneities. The B0 -dependent and B1 + -dependent data needed for deconvolving these confounding effects would increase the scan time substantially, leading to other issues such as patient tolerability. Here, we demonstrate the feasibility of brain lipid mapping using an easily implementable transient NOE (tNOE) approach. METHODS This 7T study used a frequency-selective inversion pulse at a range of frequency offsets between 1.0 and 5.0 parts per million (ppm) and -5.0 and -1.0 ppm relative to bulk water peak. This was followed by a fixed/variable mixing time and then a single-shot 2D turbo FLASH readout. The feasibility of tNOE measurements is demonstrated on bovine serum albumin phantoms and healthy human brains. RESULTS The tNOE measurements from bovine serum albumin phantoms were found to be independent of physiological pH variations. Both bovine serum albumin phantoms and human brains showed broad tNOE contributions centered at approximately -3.5 ppm relative to water peak, with presumably aliphatic moieties in lipids and proteins being the dominant contributors. Less prominent tNOE contributions of approximately +2.5 ppm relative to water, presumably from aromatic moieties, were also detected. These aromatic signals were free from any CEST signals. CONCLUSION In this study, we have demonstrated the feasibility of tNOE in human brain at 7 T. This method is more scan-time efficient than steady-state NOE and provides NOE measurement with minimal confounders.
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Affiliation(s)
- Dushyant Kumar
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Blake Benyard
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Narayan Datt Soni
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Anshuman Swain
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Neil Wilson
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Ravinder Reddy
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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Rahmanzadeh R, Weigel M, Lu PJ, Melie-Garcia L, Nguyen TD, Cagol A, La Rosa F, Barakovic M, Lutti A, Wang Y, Bach Cuadra M, Radue EW, Gaetano L, Kappos L, Kuhle J, Magon S, Granziera C. A comparative assessment of myelin-sensitive measures in multiple sclerosis patients and healthy subjects. Neuroimage Clin 2022; 36:103177. [PMID: 36067611 PMCID: PMC9468574 DOI: 10.1016/j.nicl.2022.103177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 08/22/2022] [Accepted: 08/27/2022] [Indexed: 12/14/2022]
Abstract
INTRODUCTION Multiple Sclerosis (MS) is a common neurological disease primarily characterized by myelin damage in lesions and in normal - appearing white and gray matter (NAWM, NAGM). Several quantitative MRI (qMRI) methods are sensitive to myelin characteristics by measuring specific tissue biophysical properties. However, there are currently few studies assessing the relative reproducibility and sensitivity of qMRI measures to MS pathology in vivo in patients. METHODS We performed two studies. The first study assessed of the sensitivity of qMRI measures to MS pathology: in this work, we recruited 150 MS and 100 healthy subjects, who underwent brain MRI at 3 T including quantitative T1 mapping (qT1), quantitative susceptibility mapping (QSM), magnetization transfer saturation imaging (MTsat) and myelin water imaging for myelin water fraction (MWF). The sensitivity of qMRIs to MS focal pathology (MS lesions vs peri-plaque white/gray matter (PPWM/PPGM)) was studied lesion-wise; the sensitivity to diffuse normal appearing (NA) pathology was measured using voxel-wise threshold-free cluster enhancement (TFCE) in NAWM and vertex-wise inflated cortex analysis in NAGM. Furthermore, the sensitivity of qMRI to the identification of lesion tissue was investigated using a voxel-wise logistic regression analysis to distinguish MS lesion and PP voxels. The second study assessed the reproducibility of myelin-sensitive qMRI measures in a single scanner. To evaluate the intra-session and inter-session reproducibility of qMRI measures, we have investigated 10 healthy subjects, who underwent two brain 3 T MRIs within the same day (without repositioning), and one after 1-week interval. Five region of interest (ROIs) in white and deep grey matter areas were segmented, and inter- and intra- session reproducibility was studied using the intra-class correlation coefficient (ICC). Further, we also investigated the voxel-wise reproducibility of qMRI measures in NAWM and NAGM. RESULTS qT1 and QSM showed the highest sensitivity to distinguish MS focal WM and cortical pathology from peri-plaque WM (P < 0.0001), although QSM also showed the highest variance when applied to lesions. MWF and MTsat exhibited the highest sensitivity to NAWM pathology (P < 0.01). On the other hand, qT1 appeared to be the most sensitive measure to NAGM pathology (P < 0.01). All myelin-sensitive qMRI measures exhibited high inter/intra sessional ICCs in various WM and deep GM ROIs, in NAWM and in NAGM (ICC 0.82 ± 0.12). CONCLUSION This work shows that the applied qT1, MWF, MTsat and QSM are highly reproducible and exhibit differential sensitivity to focal and diffuse WM and GM pathology in MS patients.
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Affiliation(s)
- Reza Rahmanzadeh
- Translational Imaging in Neurology Basel, Department of Medicine and Biomedical Engineering, University Hospital Basel and University of Basel, Basel, Switzerland,Neurologic Clinic and Policlinic, MS Center and Research Center for Clinical Neuroimmunology and Neuroscience Basel (RC2NB), University Hospital Basel and University of Basel, Basel, Switzerland
| | - Matthias Weigel
- Translational Imaging in Neurology Basel, Department of Medicine and Biomedical Engineering, University Hospital Basel and University of Basel, Basel, Switzerland,Neurologic Clinic and Policlinic, MS Center and Research Center for Clinical Neuroimmunology and Neuroscience Basel (RC2NB), University Hospital Basel and University of Basel, Basel, Switzerland,Division of Radiological Physics, Department of Radiology, University Hospital Basel, Basel, Switzerland
| | - Po-Jui Lu
- Translational Imaging in Neurology Basel, Department of Medicine and Biomedical Engineering, University Hospital Basel and University of Basel, Basel, Switzerland,Neurologic Clinic and Policlinic, MS Center and Research Center for Clinical Neuroimmunology and Neuroscience Basel (RC2NB), University Hospital Basel and University of Basel, Basel, Switzerland
| | - Lester Melie-Garcia
- Translational Imaging in Neurology Basel, Department of Medicine and Biomedical Engineering, University Hospital Basel and University of Basel, Basel, Switzerland,Neurologic Clinic and Policlinic, MS Center and Research Center for Clinical Neuroimmunology and Neuroscience Basel (RC2NB), University Hospital Basel and University of Basel, Basel, Switzerland
| | - Thanh D. Nguyen
- Department of Radiology, Weill Cornell Medical College, New York, NY, USA
| | - Alessandro Cagol
- Translational Imaging in Neurology Basel, Department of Medicine and Biomedical Engineering, University Hospital Basel and University of Basel, Basel, Switzerland,Neurologic Clinic and Policlinic, MS Center and Research Center for Clinical Neuroimmunology and Neuroscience Basel (RC2NB), University Hospital Basel and University of Basel, Basel, Switzerland
| | - Francesco La Rosa
- Signal Processing Laboratory (LTS5), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland,CIBM Center for Biomedical Imaging, Lausanne, Switzerland,Radiology Department, Lausanne University and University Hospital, Lausanne, Switzerland
| | - Muhamed Barakovic
- Translational Imaging in Neurology Basel, Department of Medicine and Biomedical Engineering, University Hospital Basel and University of Basel, Basel, Switzerland,Neurologic Clinic and Policlinic, MS Center and Research Center for Clinical Neuroimmunology and Neuroscience Basel (RC2NB), University Hospital Basel and University of Basel, Basel, Switzerland
| | - Antoine Lutti
- Laboratory for Research in Neuroimaging, Department of Clinical Neurosciences, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Yi Wang
- Department of Radiology, Weill Cornell Medical College, New York, NY, USA
| | - Meritxell Bach Cuadra
- Signal Processing Laboratory (LTS5), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland,CIBM Center for Biomedical Imaging, Lausanne, Switzerland,Radiology Department, Lausanne University and University Hospital, Lausanne, Switzerland
| | - Ernst-Wilhelm Radue
- Translational Imaging in Neurology Basel, Department of Medicine and Biomedical Engineering, University Hospital Basel and University of Basel, Basel, Switzerland
| | | | - Ludwig Kappos
- Neurologic Clinic and Policlinic, MS Center and Research Center for Clinical Neuroimmunology and Neuroscience Basel (RC2NB), University Hospital Basel and University of Basel, Basel, Switzerland
| | - Jens Kuhle
- Neurologic Clinic and Policlinic, MS Center and Research Center for Clinical Neuroimmunology and Neuroscience Basel (RC2NB), University Hospital Basel and University of Basel, Basel, Switzerland
| | - Stefano Magon
- Pharmaceutical Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Basel, Switzerland
| | - Cristina Granziera
- Translational Imaging in Neurology Basel, Department of Medicine and Biomedical Engineering, University Hospital Basel and University of Basel, Basel, Switzerland,Neurologic Clinic and Policlinic, MS Center and Research Center for Clinical Neuroimmunology and Neuroscience Basel (RC2NB), University Hospital Basel and University of Basel, Basel, Switzerland,Corresponding author.
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6
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Fischi-Gomez E, Girard G, Koch PJ, Yu T, Pizzolato M, Brügger J, Piredda GF, Hilbert T, Cadic-Melchior AG, Beanato E, Park CH, Morishita T, Wessel MJ, Schiavi S, Daducci A, Kober T, Canales-Rodríguez EJ, Hummel FC, Thiran JP. Variability and reproducibility of multi-echo T2 relaxometry: Insights from multi-site, multi-session and multi-subject MRI acquisitions. Front Radiol 2022; 2:930666. [PMID: 37492668 PMCID: PMC10365099 DOI: 10.3389/fradi.2022.930666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Accepted: 06/30/2022] [Indexed: 07/27/2023]
Abstract
Quantitative magnetic resonance imaging (qMRI) can increase the specificity and sensitivity of conventional weighted MRI to underlying pathology by comparing meaningful physical or chemical parameters, measured in physical units, with normative values acquired in a healthy population. This study focuses on multi-echo T2 relaxometry, a qMRI technique that probes the complex tissue microstructure by differentiating compartment-specific T2 relaxation times. However, estimation methods are still limited by their sensitivity to the underlying noise. Moreover, estimating the model's parameters is challenging because the resulting inverse problem is ill-posed, requiring advanced numerical regularization techniques. As a result, the estimates from distinct regularization strategies are different. In this work, we aimed to investigate the variability and reproducibility of different techniques for estimating the transverse relaxation time of the intra- and extra-cellular space (T2IE) in gray (GM) and white matter (WM) tissue in a clinical setting, using a multi-site, multi-session, and multi-run T2 relaxometry dataset. To this end, we evaluated three different techniques for estimating the T2 spectra (two regularized non-negative least squares methods and a machine learning approach). Two independent analyses were performed to study the effect of using raw and denoised data. For both the GM and WM regions, and the raw and denoised data, our results suggest that the principal source of variance is the inter-subject variability, showing a higher coefficient of variation (CoV) than those estimated for the inter-site, inter-session, and inter-run, respectively. For all reconstruction methods studied, the CoV ranged between 0.32 and 1.64%. Interestingly, the inter-session variability was close to the inter-scanner variability with no statistical differences, suggesting that T2IE is a robust parameter that could be employed in multi-site neuroimaging studies. Furthermore, the three tested methods showed consistent results and similar intra-class correlation (ICC), with values superior to 0.7 for most regions. Results from raw data were slightly more reproducible than those from denoised data. The regularized non-negative least squares method based on the L-curve technique produced the best results, with ICC values ranging from 0.72 to 0.92.
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Affiliation(s)
- Elda Fischi-Gomez
- Signal Processing Laboratory 5 (LTS5), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
- Translational Machine Learning Lab, Department of Radiology, Centre Hospitalier Universitaire Vaudois, University of Lausanne, Lausanne, Switzerland
| | - Gabriel Girard
- Signal Processing Laboratory 5 (LTS5), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
- CIBM Center for Biomedical Imaging, Lausanne, Switzerland
- Department of Radiology, Centre Hospitalier Universitaire Vaudois, University of Lausanne, Lausanne, Switzerland
| | - Philipp J. Koch
- Defitech Chair for Clinical Neuroengineering, Neuro-X Institute (NIX) and Brain Mind Institute (BMI), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
- Defitech Chair of Clinical Neuroengineering, Neuro-X Institute (NIX) and Brain Mind Institute (BMI), École Polytechnique Fédérale de Lausanne (EPFL Valais), Clinique Romande de Réadaptation, Sion, Switzerland
- Department of Neurology, University of Lübeck, Lübeck, Germany
- Center of Brain, Behavior and Metabolism (CBBM), University of Lübeck, Lübeck, Germany
| | - Thomas Yu
- Signal Processing Laboratory 5 (LTS5), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
- Advanced Clinical Imaging Technology, Siemens Healthineers International AG, Lausanne, Switzerland
| | - Marco Pizzolato
- Signal Processing Laboratory 5 (LTS5), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
- Department of Applied Mathematics and Computer Science, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Julia Brügger
- Defitech Chair for Clinical Neuroengineering, Neuro-X Institute (NIX) and Brain Mind Institute (BMI), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
- Defitech Chair of Clinical Neuroengineering, Neuro-X Institute (NIX) and Brain Mind Institute (BMI), École Polytechnique Fédérale de Lausanne (EPFL Valais), Clinique Romande de Réadaptation, Sion, Switzerland
| | - Gian Franco Piredda
- Signal Processing Laboratory 5 (LTS5), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
- Department of Radiology, Centre Hospitalier Universitaire Vaudois, University of Lausanne, Lausanne, Switzerland
- Advanced Clinical Imaging Technology, Siemens Healthineers International AG, Lausanne, Switzerland
| | - Tom Hilbert
- Signal Processing Laboratory 5 (LTS5), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
- Department of Radiology, Centre Hospitalier Universitaire Vaudois, University of Lausanne, Lausanne, Switzerland
- Advanced Clinical Imaging Technology, Siemens Healthineers International AG, Lausanne, Switzerland
| | - Andéol G. Cadic-Melchior
- Defitech Chair for Clinical Neuroengineering, Neuro-X Institute (NIX) and Brain Mind Institute (BMI), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
- Defitech Chair of Clinical Neuroengineering, Neuro-X Institute (NIX) and Brain Mind Institute (BMI), École Polytechnique Fédérale de Lausanne (EPFL Valais), Clinique Romande de Réadaptation, Sion, Switzerland
| | - Elena Beanato
- Defitech Chair for Clinical Neuroengineering, Neuro-X Institute (NIX) and Brain Mind Institute (BMI), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
- Defitech Chair of Clinical Neuroengineering, Neuro-X Institute (NIX) and Brain Mind Institute (BMI), École Polytechnique Fédérale de Lausanne (EPFL Valais), Clinique Romande de Réadaptation, Sion, Switzerland
| | - Chang-Hyun Park
- Defitech Chair for Clinical Neuroengineering, Neuro-X Institute (NIX) and Brain Mind Institute (BMI), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
- Defitech Chair of Clinical Neuroengineering, Neuro-X Institute (NIX) and Brain Mind Institute (BMI), École Polytechnique Fédérale de Lausanne (EPFL Valais), Clinique Romande de Réadaptation, Sion, Switzerland
| | - Takuya Morishita
- Defitech Chair for Clinical Neuroengineering, Neuro-X Institute (NIX) and Brain Mind Institute (BMI), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
- Defitech Chair of Clinical Neuroengineering, Neuro-X Institute (NIX) and Brain Mind Institute (BMI), École Polytechnique Fédérale de Lausanne (EPFL Valais), Clinique Romande de Réadaptation, Sion, Switzerland
| | - Maximilian J. Wessel
- Defitech Chair for Clinical Neuroengineering, Neuro-X Institute (NIX) and Brain Mind Institute (BMI), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
- Defitech Chair of Clinical Neuroengineering, Neuro-X Institute (NIX) and Brain Mind Institute (BMI), École Polytechnique Fédérale de Lausanne (EPFL Valais), Clinique Romande de Réadaptation, Sion, Switzerland
- Department of Neurology, University Hospital and Julius-Maximilians-University, Wuerzburg, Germany
| | - Simona Schiavi
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health (DINOGMI), University of Genoa, Genoa, Italy
- Diffusion Imaging and Connectivity Estimation (DICE) Lab, Department of Computer Science, University of Verona, Verona, Italy
| | - Alessandro Daducci
- Diffusion Imaging and Connectivity Estimation (DICE) Lab, Department of Computer Science, University of Verona, Verona, Italy
| | - Tobias Kober
- Signal Processing Laboratory 5 (LTS5), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
- Department of Radiology, Centre Hospitalier Universitaire Vaudois, University of Lausanne, Lausanne, Switzerland
- Advanced Clinical Imaging Technology, Siemens Healthineers International AG, Lausanne, Switzerland
| | - Erick J. Canales-Rodríguez
- Signal Processing Laboratory 5 (LTS5), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Friedhelm C. Hummel
- Defitech Chair for Clinical Neuroengineering, Neuro-X Institute (NIX) and Brain Mind Institute (BMI), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
- Defitech Chair of Clinical Neuroengineering, Neuro-X Institute (NIX) and Brain Mind Institute (BMI), École Polytechnique Fédérale de Lausanne (EPFL Valais), Clinique Romande de Réadaptation, Sion, Switzerland
- Clinical Neuroscience, University Hospital of Geneva (HUG), Geneva, Switzerland
| | - Jean-Philippe Thiran
- Signal Processing Laboratory 5 (LTS5), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
- CIBM Center for Biomedical Imaging, Lausanne, Switzerland
- Department of Radiology, Centre Hospitalier Universitaire Vaudois, University of Lausanne, Lausanne, Switzerland
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7
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Mehdizadeh N, Wilman AH. Myelin water fraction mapping from multiple echo spin echoes and an independent B 1 + map. Magn Reson Med 2022; 88:1380-1390. [PMID: 35576121 PMCID: PMC9321077 DOI: 10.1002/mrm.29286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 03/23/2022] [Accepted: 04/13/2022] [Indexed: 11/11/2022]
Abstract
Purpose Myelin water fraction (MWF) is often obtained from a multiple echo spin echo (MESE) sequence using multi‐component T2 fitting with non‐negative least squares. This process fits many unknowns including B1+ to produce a T2 spectrum for each voxel. Presented is an alternative using a rapid B1+ mapping sequence to supply B1+ for the MWF fitting procedure. Methods Effects of B1+ errors on MWF calculations were modeled for 2D and 3D MESE using Bloch and extended phase graph simulations, respectively. Variations in SNR and relative refocusing widths were tested. Human brain experiments at 3 T used 2D MESE and an independent B1+ map. MWF maps were produced with the standard approach and with the use of the independent B1+ map. Differences in B1+ and mean MWF in specific brain regions were compared. Results For 2D MESE, MWF with the standard method was strongly affected by B1+ misestimations arising from limited SNR and response asymmetry around 180°, which decreased with increasing relative refocusing width. Using an independent B1+ map increased mean MWF and decreased coefficient of variation. Notable differences in vivo in 2D MESE were in areas of high B1+ such as thalamus and splenium where mean MWF increased by 88% and 31%, respectively (P < 0.001). Simulations also demonstrated the advantages of this approach for 3D MESE when SNR is <500. Conclusion For 2D MESE, because of increased complexity of decay curves and limited SNR, supplying B1+ improves MWF results in peripheral and central brain regions where flip angles differ substantially from 180°.
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Affiliation(s)
- Nima Mehdizadeh
- Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada
| | - Alan H Wilman
- Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada
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8
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Bontempi P, Scartoni D, Amelio D, Cianchetti M, Turkaj A, Amichetti M, Farace P. Multicomponent T 2 relaxometry reveals early myelin white matter changes induced by proton radiation treatment. Magn Reson Med 2021; 86:3236-3245. [PMID: 34268786 DOI: 10.1002/mrm.28913] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 05/21/2021] [Accepted: 06/14/2021] [Indexed: 11/11/2022]
Abstract
PURPOSE To investigate MRI myelin water imaging (MWI) by multicomponent T2 relaxometry as a quantitative imaging biomarker for brain radiation-induced changes and to compare it with DTI. METHODS Sixteen patients underwent fractionated proton therapy (PT) receiving dose to the healthy tissue because of direct or indirect (base skull tumors) irradiation. MWI was performed by a multi-echo sequence with 32 equally spaced echoes (10-320 ms). Decay data were processed to identify 3 T2 compartments: myelin water (Mw) below 40 ms, intra-extracellular water (IEw) between 40 and 250 ms, and free water (CSFw) above 250 ms. Both MWI and DTI scans were acquired pre (pre)-treatment and immediately at the end (end) of PT. After image registration, voxel-wise difference maps, obtained by subtracting MWI and DTI pre from those acquired at the end of PT, were compared with the corresponding biological equivalent dose (BED). RESULTS Mw difference showed a positive correlation and IEw difference showed a negative correlation with BED considering end-pre changes (P < .01). The changes in CSFw were not significantly correlated with the delivered BED. The changes in DTI data, considering end-pre acquisitions, showed a positive correlation between fractional anisotropy and the delivered BED. CONCLUSION MWI might detect early white matter radiation-induced alterations, providing additional information to DTI, which might improve the understanding of the pathogenesis of the radiation damage.
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Affiliation(s)
- Pietro Bontempi
- Proton Therapy Unit, Hospital of Trento, Azienda Provinciale per i Servizi Sanitari (APSS), Trento, Italy
| | - Daniele Scartoni
- Proton Therapy Unit, Hospital of Trento, Azienda Provinciale per i Servizi Sanitari (APSS), Trento, Italy
| | - Dante Amelio
- Proton Therapy Unit, Hospital of Trento, Azienda Provinciale per i Servizi Sanitari (APSS), Trento, Italy
| | - Marco Cianchetti
- Proton Therapy Unit, Hospital of Trento, Azienda Provinciale per i Servizi Sanitari (APSS), Trento, Italy
| | - Ana Turkaj
- Proton Therapy Unit, Hospital of Trento, Azienda Provinciale per i Servizi Sanitari (APSS), Trento, Italy
| | - Maurizio Amichetti
- Proton Therapy Unit, Hospital of Trento, Azienda Provinciale per i Servizi Sanitari (APSS), Trento, Italy
| | - Paolo Farace
- Proton Therapy Unit, Hospital of Trento, Azienda Provinciale per i Servizi Sanitari (APSS), Trento, Italy
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9
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Granziera C, Wuerfel J, Barkhof F, Calabrese M, De Stefano N, Enzinger C, Evangelou N, Filippi M, Geurts JJG, Reich DS, Rocca MA, Ropele S, Rovira À, Sati P, Toosy AT, Vrenken H, Gandini Wheeler-Kingshott CAM, Kappos L. Quantitative magnetic resonance imaging towards clinical application in multiple sclerosis. Brain 2021; 144:1296-1311. [PMID: 33970206 PMCID: PMC8219362 DOI: 10.1093/brain/awab029] [Citation(s) in RCA: 60] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 10/25/2020] [Accepted: 11/16/2020] [Indexed: 12/11/2022] Open
Abstract
Quantitative MRI provides biophysical measures of the microstructural integrity of the CNS, which can be compared across CNS regions, patients, and centres. In patients with multiple sclerosis, quantitative MRI techniques such as relaxometry, myelin imaging, magnetization transfer, diffusion MRI, quantitative susceptibility mapping, and perfusion MRI, complement conventional MRI techniques by providing insight into disease mechanisms. These include: (i) presence and extent of diffuse damage in CNS tissue outside lesions (normal-appearing tissue); (ii) heterogeneity of damage and repair in focal lesions; and (iii) specific damage to CNS tissue components. This review summarizes recent technical advances in quantitative MRI, existing pathological validation of quantitative MRI techniques, and emerging applications of quantitative MRI to patients with multiple sclerosis in both research and clinical settings. The current level of clinical maturity of each quantitative MRI technique, especially regarding its integration into clinical routine, is discussed. We aim to provide a better understanding of how quantitative MRI may help clinical practice by improving stratification of patients with multiple sclerosis, and assessment of disease progression, and evaluation of treatment response.
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Affiliation(s)
- Cristina Granziera
- Neurologic Clinic and Policlinic, Departments of Medicine, Clinical Research and Biomedical Engineering, University Hospital Basel and University of Basel, Basel, Switzerland
- Translational Imaging in Neurology (ThINk) Basel, Department of Biomedical Engineering, University Hospital Basel and University of Basel, Basel, Switzerland
| | - Jens Wuerfel
- Medical Image Analysis Center, Basel, Switzerland
- Quantitative Biomedical Imaging Group (qbig), Department of Biomedical Engineering, University of Basel, Basel, Switzerland
| | - Frederik Barkhof
- Department of Radiology and Nuclear Medicine, Amsterdam Neuroscience, multiple sclerosis Center Amsterdam, Amsterdam University Medical Center, Amsterdam, The Netherlands
- UCL Institutes of Healthcare Engineering and Neurology, London, UK
| | - Massimiliano Calabrese
- Neurology B, Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Nicola De Stefano
- Neurology, Department of Medicine, Surgery and Neuroscience, University of Siena, Italy
| | - Christian Enzinger
- Department of Neurology and Division of Neuroradiology, Medical University of Graz, Graz, Austria
| | - Nikos Evangelou
- Division of Clinical Neuroscience, University of Nottingham, Nottingham, UK
| | - Massimo Filippi
- Neuroimaging Research Unit, Institute of Experimental Neurology, Division of Neuroscience, and Neurology Unit, IRCCS San Raffaele Scientific Institute, Milan, Italy
- Vita-Salute San Raffaele University, Milan, Italy
| | - Jeroen J G Geurts
- Department of Anatomy and Neurosciences, multiple sclerosis Center Amsterdam, Neuroscience Amsterdam, Amsterdam University Medical Centers, location VUmc, Amsterdam, The Netherlands
| | - Daniel S Reich
- Translational Neuroradiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health (NIH), Bethesda, MD, USA
| | - Maria A Rocca
- Neuroimaging Research Unit, Institute of Experimental Neurology, Division of Neuroscience, and Neurology Unit, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Stefan Ropele
- Neuroimaging Research Unit, Department of Neurology, Medical University of Graz, Graz, Austria
| | - Àlex Rovira
- Section of Neuroradiology (Department of Radiology), Vall d'Hebron University Hospital and Research Institute, Barcelona, Spain
| | - Pascal Sati
- Translational Neuroradiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health (NIH), Bethesda, MD, USA
- Department of Neurology, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Ahmed T Toosy
- Queen Square multiple sclerosis Centre, Department of Neuroinflammation, Queen Square Institute of Neurology, University College London, London, UK
| | - Hugo Vrenken
- Department of Radiology and Nuclear Medicine, Amsterdam Neuroscience, multiple sclerosis Center Amsterdam, Amsterdam University Medical Center, Amsterdam, The Netherlands
| | - Claudia A M Gandini Wheeler-Kingshott
- Queen Square multiple sclerosis Centre, Department of Neuroinflammation, Queen Square Institute of Neurology, University College London, London, UK
- Department of Brain and Behavioural Sciences, University of Pavia, Pavia, Italy
- Brain MRI 3T Research Centre, IRCCS Mondino Foundation, Pavia, Italy
| | - Ludwig Kappos
- Neurologic Clinic and Policlinic, Departments of Medicine, Clinical Research and Biomedical Engineering, University Hospital Basel and University of Basel, Basel, Switzerland
- Translational Imaging in Neurology (ThINk) Basel, Department of Biomedical Engineering, University Hospital Basel and University of Basel, Basel, Switzerland
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10
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Wiggermann V, MacKay AL, Rauscher A, Helms G. In vivo investigation of the multi-exponential T 2 decay in human white matter at 7 T: Implications for myelin water imaging at UHF. NMR Biomed 2021; 34:e4429. [PMID: 33118238 DOI: 10.1002/nbm.4429] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 08/23/2020] [Accepted: 09/22/2020] [Indexed: 06/11/2023]
Abstract
INTRODUCTION Multi-component T2 mapping using a gradient- and spin-echo (GraSE) acquisition has become standard for myelin water imaging at 3 T. Higher magnetic field strengths promise signal-to-noise ratio benefits but face specific absorption rate limits and shortened T2 times. This study investigates compartmental T2 times in vivo and addresses advantages and challenges of multi-component T2 mapping at 7 T. METHODS We acquired 3D multi-echo GraSE data in seven healthy adults at 7 T, with three subjects also scanned at 3 T. Stimulated echoes arising from B1+ inhomogeneities were accounted for by the extended phase graph (EPG) algorithm. We used the computed T2 distributions to determine T2 times that identify different water pools and assessed signal-to-noise and fit-to-noise characteristics of the signal estimation. We compared short T2 fractions and T2 properties of the intermediate water pool at 3 T and 7 T. RESULTS Flip angle mapping confirmed that EPG accurately determined the larger B1+ inhomogeneity at 7 T. Multi-component T2 analysis demonstrated shortened T2 times at 7 T compared with 3 T. Fit-to-noise and signal-to-noise ratios were improved at 7 T but depended on B1+ homogeneity. Adjusting the shortest T2 to 8 ms and the T2 threshold that separates different water compartments to 20 ms yielded short T2 fractions at 7 T that conformed to 3 T data. Short T2 fractions in myelin-rich white matter regions were lower at 7 T than at 3 T, and higher in iron-rich structures. DISCUSSION Adjusting the T2 compartment boundaries was required due to the shorter T2 relaxation times at 7 T. Shorter echo spacing would better sample the fast decaying signal but would increase peripheral nerve stimulation. Multi-channel transmission will improve T2 measurements at 7 T. CONCLUSION We used a multi-echo 3D GraSE sequence to characterize the multi-exponential T2 decay at 7 T. We adapted T2 parameters for evaluation of the short T2 fraction. Obtained 7 T multi-component T2 maps were in good agreement with 3 T data.
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Affiliation(s)
- Vanessa Wiggermann
- Department of Physics and Astronomy, University of British Columbia, Vancouver, Canada
- Department of Pediatrics, University of British Columbia, Vancouver, Canada
- UBC MRI Research Centre, University of British Columbia, Vancouver, Canada
| | - Alexander L MacKay
- Department of Physics and Astronomy, University of British Columbia, Vancouver, Canada
- UBC MRI Research Centre, University of British Columbia, Vancouver, Canada
- Department of Radiology, University of British Columbia, Vancouver, Canada
| | - Alexander Rauscher
- Department of Physics and Astronomy, University of British Columbia, Vancouver, Canada
- Department of Pediatrics, University of British Columbia, Vancouver, Canada
- UBC MRI Research Centre, University of British Columbia, Vancouver, Canada
- BC Children's Hospital Research Institute, University of British Columbia, Vancouver, Canada
| | - Gunther Helms
- Medical Radiation Physics, Department of Clinical Sciences Lund, Lund University, Lund, Sweden
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11
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Meissner TW, Genç E, Mädler B, Weigelt S. Myelin development in visual scene-network tracts beyond late childhood: A multimethod neuroimaging study. Cortex 2021; 137:18-34. [PMID: 33588130 DOI: 10.1016/j.cortex.2020.12.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 07/30/2020] [Accepted: 12/14/2020] [Indexed: 12/15/2022]
Abstract
The visual scene-network-comprising the parahippocampal place area (PPA), retrosplenial cortex (RSC), and occipital place area (OPA)-shows a prolonged functional development. Structural development of white matter that underlies the scene-network has not been investigated despite its potential influence on scene-network function. The key factor for white matter maturation is myelination. However, research on myelination using the gold standard method of post-mortem histology is scarce. In vivo alternatives diffusion-weighted imaging (DWI) and myelin water imaging (MWI) so far report broad-scale findings that prohibit inferences concerning the scene-network. Here, we combine MWI, DWI tractography, and fMRI to investigate myelination in scene-network tracts in middle childhood, late childhood, and adulthood. We report increasing myelin from middle childhood to adulthood in right PPA-OPA, and trends towards increases in the left and right RSC-OPA tracts. Investigating tracts to regions highly connected with the scene-network, such as early visual cortex and the hippocampus, did not yield any significant age group differences. Our findings indicate that structural development coincides with functional development in the scene-network, possibly enabling structure-function interactions.
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12
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Wiggermann V, Vavasour IM, Kolind SH, MacKay AL, Helms G, Rauscher A. Non-negative least squares computation for in vivo myelin mapping using simulated multi-echo spin-echo T 2 decay data. NMR Biomed 2020; 33:e4277. [PMID: 32124505 DOI: 10.1002/nbm.4277] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 01/20/2020] [Accepted: 01/26/2020] [Indexed: 06/10/2023]
Abstract
Multi-compartment T2 mapping has gained particular relevance for the study of myelin water in the brain. As a facilitator of rapid saltatory axonal signal transmission, myelin is a cornerstone indicator of white matter development and function. Regularized non-negative least squares fitting of multi-echo T2 data has been widely employed for the computation of the myelin water fraction (MWF), and the obtained MWF maps have been histopathologically validated. MWF measurements depend upon the quality of the data acquisition, B1+ homogeneity and a range of fitting parameters. In this special issue article, we discuss the relevance of these factors for the accurate computation of multi-compartment T2 and MWF maps. We generated multi-echo spin-echo T2 decay curves following the Carr-Purcell-Meiboom-Gill approach for various myelin concentrations and myelin T2 scenarios by simulating the evolution of the magnetization vector between echoes based on the Bloch equations. We demonstrated that noise and imperfect refocusing flip angles yield systematic underestimations in MWF and intra-/extracellular water geometric mean T2 (gmT2 ). MWF estimates were more stable than myelin water gmT2 time across different settings of the T2 analysis. We observed that the lower limit of the T2 distribution grid should be slightly shorter than TE1 . Both TE1 and the acquisition echo spacing also have to be sufficiently short to capture the rapidly decaying myelin water T2 signal. Among all parameters of interest, the estimated MWF and intra-/extracellular water gmT2 differed by approximately 0.13-4 percentage points and 3-4 ms, respectively, from the true values, with larger deviations observed in the presence of greater B1+ inhomogeneities and at lower signal-to-noise ratio. Tailoring acquisition strategies may allow us to better characterize the T2 distribution, including the myelin water, in vivo.
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Affiliation(s)
- V Wiggermann
- Department of Physics and Astronomy, University of British Columbia, Vancouver, Canada
- Department of Pediatrics, University of British Columbia, Vancouver, Canada
- UBC MRI Research Center, University of British Columbia, Vancouver, Canada
| | - I M Vavasour
- UBC MRI Research Center, University of British Columbia, Vancouver, Canada
- Department of Radiology, University of British Columbia, Vancouver, Canada
| | - S H Kolind
- Department of Physics and Astronomy, University of British Columbia, Vancouver, Canada
- UBC MRI Research Center, University of British Columbia, Vancouver, Canada
- Department of Radiology, University of British Columbia, Vancouver, Canada
- Department of Medicine (Division Neurology), University of British Columbia, Vancouver, Canada
| | - A L MacKay
- Department of Physics and Astronomy, University of British Columbia, Vancouver, Canada
- UBC MRI Research Center, University of British Columbia, Vancouver, Canada
- Department of Radiology, University of British Columbia, Vancouver, Canada
| | - G Helms
- Department of Clinical Sciences Lund (IKVL), Medical Radiation Physics, Lund University, Lund, Sweden
| | - A Rauscher
- Department of Physics and Astronomy, University of British Columbia, Vancouver, Canada
- Department of Pediatrics, University of British Columbia, Vancouver, Canada
- UBC MRI Research Center, University of British Columbia, Vancouver, Canada
- Department of Radiology, University of British Columbia, Vancouver, Canada
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13
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van der Weijden CWJ, García DV, Borra RJH, Thurner P, Meilof JF, van Laar PJ, Dierckx RAJO, Gutmann IW, de Vries EFJ. Myelin quantification with MRI: A systematic review of accuracy and reproducibility. Neuroimage 2020; 226:117561. [PMID: 33189927 DOI: 10.1016/j.neuroimage.2020.117561] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 10/27/2020] [Accepted: 11/07/2020] [Indexed: 12/29/2022] Open
Abstract
OBJECTIVES Currently, multiple sclerosis is treated with anti-inflammatory therapies, but these treatments lack efficacy in progressive disease. New treatment strategies aim to repair myelin damage and efficacy evaluation of such new therapies would benefit from validated myelin imaging techniques. Several MRI methods for quantification of myelin density are available now. This systematic review aims to analyse the performance of these MRI methods. METHODS Studies comparing myelin quantification by MRI with histology, the current gold standard, or assessing reproducibility were retrieved from PubMed/MEDLINE and Embase (until December 2019). Included studies assessed both myelin histology and MRI quantitatively. Correlation or variance measurements were extracted from the studies. Non-parametric tests were used to analyse differences in study methodologies. RESULTS The search yielded 1348 unique articles. Twenty-two animal studies and 13 human studies correlated myelin MRI with histology. Eighteen clinical studies analysed the reproducibility. Overall bias risk was low or unclear. All MRI methods performed comparably, with a mean correlation between MRI and histology of R2=0.54 (SD=0.30) for animal studies, and R2=0.54 (SD=0.18) for human studies. Reproducibility for the MRI methods was good (ICC=0.75-0.93, R2=0.90-0.98, COV=1.3-27%), except for MTR (ICC=0.05-0.51). CONCLUSIONS Overall, MRI-based myelin imaging methods show a fairly good correlation with histology and a good reproducibility. However, the amount of validation data is too limited and the variability in performance between studies is too large to select the optimal MRI method for myelin quantification yet.
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Affiliation(s)
- Chris W J van der Weijden
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713 GZ Groningen, the Netherlands.
| | - David Vállez García
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713 GZ Groningen, the Netherlands; Department of Radiology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713 GZ Groningen, the Netherlands.
| | - Ronald J H Borra
- Department of Radiology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713 GZ Groningen, the Netherlands.
| | - Patrick Thurner
- Universitätsklinik für Radiologie und Nuklearmedizin, Medizinische Universität Wien, Währinger Gürtel 18-20, 1090 Wien, Austria.
| | - Jan F Meilof
- Multiple Sclerosis Center Noord Nederland, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713 GZ Groningen, the Netherlands.
| | - Peter-Jan van Laar
- Department of Radiology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713 GZ Groningen, the Netherlands; Department of Radiology, Zorggroep Twente, Zilvermeeuw 1, 7609 PP Almelo, the Netherlands.
| | - Rudi A J O Dierckx
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713 GZ Groningen, the Netherlands.
| | - Ingomar W Gutmann
- Physics of Functional Material, Faculty of Physics, University of Vienna, Boltzmanngasse 5, 1090 Vienna, Austria.
| | - Erik F J de Vries
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713 GZ Groningen, the Netherlands.
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14
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Weber AM, Zhang Y, Kames C, Rauscher A. Myelin water imaging and R 2* mapping in neonates: Investigating R 2* dependence on myelin and fibre orientation in whole brain white matter. NMR Biomed 2020; 33:e4222. [PMID: 31846134 DOI: 10.1002/nbm.4222] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 09/27/2019] [Accepted: 10/20/2019] [Indexed: 06/10/2023]
Abstract
R2* relaxation provides a semiquantitative method of detecting myelin, iron and white matter fibre orientation angles. Compared with standard histogram-based analyses, angle-resolved analysis of R2* has previously been shown to substantially improve the detection of subtle differences in the brain between healthy siblings of subjects with multiple sclerosis and unrelated healthy controls. Neonates, who are born with very little myelin and iron, and an underdeveloped connectome, provide researchers with an opportunity to investigate whether R2* is intimately linked with fibre-angle or myelin content as it is in adults, which may in future studies be explored as a potential white matter developmental biomarker. Five healthy adult volunteers (mean age [±SD] = 31.2 [±8.3] years; three males) were recruited from Vancouver, Canada. Eight term neonates (mean age = 38.6 ± 1.2 weeks; five males) were recruited from the Children's Hospital of Chongqing Medical University neonatal ward. All subjects were scanned on identical 3 T Philips Achieva scanners equipped with an eight-channel SENSE head coil and underwent a multiecho gradient echo scan, a 32-direction DTI scan and a myelin water imaging scan. For both neonates and adults, bin-averaged R2* variation across the brain's white matter was found to be best explained by fibre orientation. For adults, this represented a difference in R2* values of 3.5 Hz from parallel to perpendicular fibres with respect to the main magnetic field. In neonates, the fibre orientation dependency displayed a cosine wave shape, with a small R2* range of 0.4 Hz. This minor relationship in neonates provides further evidence for the key role myelin probably plays in creating this fibre orientation dependence later in life, but suggests limited clinical application in newborn populations. Future studies should investigate fibre-orientation dependency in infants in the first 5 years, when substantial myelin development occurs.
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Affiliation(s)
- Alexander Mark Weber
- Division of Neurology, Department of Pediatrics, University of British Columbia, Vancouver, BC, Canada
- UBC MRI Research Centre, University of British Columbia, Vancouver, BC, Canada
| | - Yuting Zhang
- Department of Radiology, Children's Hospital of Chongqing Medical University, Chongqing, China
- Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Medical University, Chongqing, China
- Key Laboratory of Pediatrics in Chongqing, Chongqing Medical University, Chongqing, China
- Chongqing International Science and Technology Cooperation Center for Child Development and Disorders, Chongqing, China
| | - Christian Kames
- UBC MRI Research Centre, University of British Columbia, Vancouver, BC, Canada
- Department of Physics & Astronomy, University of British Columbia, Vancouver, BC, Canada
| | - Alexander Rauscher
- Division of Neurology, Department of Pediatrics, University of British Columbia, Vancouver, BC, Canada
- UBC MRI Research Centre, University of British Columbia, Vancouver, BC, Canada
- Department of Physics & Astronomy, University of British Columbia, Vancouver, BC, Canada
- Department of Radiology, University of British Columbia, Vancouver, BC, Canada
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15
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Dvorak AV, Wiggermann V, Gilbert G, Vavasour IM, MacMillan EL, Barlow L, Wiley N, Kozlowski P, MacKay AL, Rauscher A, Kolind SH. Multi-spin echo T 2 relaxation imaging with compressed sensing (METRICS) for rapid myelin water imaging. Magn Reson Med 2020; 84:1264-1279. [PMID: 32065474 DOI: 10.1002/mrm.28199] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 12/20/2019] [Accepted: 01/13/2020] [Indexed: 12/11/2022]
Abstract
PURPOSE Myelin water imaging (MWI) provides a valuable biomarker for myelin, but clinical application has been restricted by long acquisition times. Accelerating the standard multi-echo T2 acquisition with gradient echoes (GRASE) or by 2D multi-slice data collection results in image blurring, contrast changes, and other issues. Compressed sensing (CS) can vastly accelerate conventional MRI. In this work, we assessed the use of CS for in vivo human MWI, using a 3D multi spin-echo sequence. METHODS We implemented multi-echo T2 relaxation imaging with compressed sensing (METRICS) and METRICS with partial Fourier acceleration (METRICS-PF). Scan-rescan data were acquired from 12 healthy controls for assessment of repeatability. MWI data were acquired for METRICS in 9 m:58 s and for METRICS-PF in 7 m:25 s, both with 1.5 × 2 × 3 mm3 voxels, 56 echoes, 7 ms ΔTE, and 240 × 240 × 170 mm3 FOV. METRICS was compared with a novel multi-echo spin-echo gold-standard (MSE-GS) MWI acquisition, acquired for a single additional subject in 2 h:2 m:40 s. RESULTS METRICS/METRICS-PF myelin water fraction had mean: repeatability coefficient 1.5/1.1, coefficient of variation 6.2/4.5%, and intra-class correlation coefficient 0.79/0.84. Repeatability metrics comparing METRICS with METRICS-PF were similar, and both sequences agreed with reference values from literature. METRICS images and quantitative maps showed excellent qualitative agreement with those of MSE-GS. CONCLUSION METRICS and METRICS-PF provided highly repeatable MWI data without the inherent disadvantages of GRASE or 2D multi-slice acquisition. CS acceleration allows MWI data to be acquired rapidly with larger FOV, higher estimated SNR, more isotropic voxels and more echoes than with previous techniques. The approach introduced here generalizes to any multi-component T2 mapping application.
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Affiliation(s)
- Adam V Dvorak
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada.,International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, British Columbia, Canada
| | - Vanessa Wiggermann
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada.,Department of Pediatrics, University of British Columbia, Vancouver, British Columbia, Canada.,UBC MRI Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
| | | | - Irene M Vavasour
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada.,Department of Radiology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Erin L MacMillan
- UBC MRI Research Centre, University of British Columbia, Vancouver, British Columbia, Canada.,MR Clinical Science, Philips Canada, Markham, Ontario, Canada.,Department of Radiology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Laura Barlow
- UBC MRI Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
| | - Neale Wiley
- UBC MRI Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
| | - Piotr Kozlowski
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, British Columbia, Canada.,UBC MRI Research Centre, University of British Columbia, Vancouver, British Columbia, Canada.,Department of Radiology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Alex L MacKay
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada.,UBC MRI Research Centre, University of British Columbia, Vancouver, British Columbia, Canada.,Department of Radiology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Alexander Rauscher
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada.,Department of Pediatrics, University of British Columbia, Vancouver, British Columbia, Canada.,UBC MRI Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
| | - Shannon H Kolind
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada.,International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, British Columbia, Canada.,UBC MRI Research Centre, University of British Columbia, Vancouver, British Columbia, Canada.,Department of Radiology, University of British Columbia, Vancouver, British Columbia, Canada.,Division of Neurology, Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
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Drenthen GS, Backes WH, Aldenkamp AP, Jansen JF. Applicability and reproducibility of 2D multi-slice GRASE myelin water fraction with varying acquisition acceleration. Neuroimage 2019; 195:333-339. [DOI: 10.1016/j.neuroimage.2019.04.011] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 03/20/2019] [Accepted: 04/03/2019] [Indexed: 12/12/2022] Open
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17
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Kor D, Birkl C, Ropele S, Doucette J, Xu T, Wiggermann V, Hernández-Torres E, Hametner S, Rauscher A. The role of iron and myelin in orientation dependent R 2* of white matter. NMR Biomed 2019; 32:e4092. [PMID: 31038240 DOI: 10.1002/nbm.4092] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 02/05/2019] [Accepted: 02/17/2019] [Indexed: 06/09/2023]
Abstract
Brain myelin and iron content are important parameters in neurodegenerative diseases such as multiple sclerosis (MS). Both myelin and iron content influence the brain's R2* relaxation rate. However, their quantification based on R2* maps requires a realistic tissue model that can be fitted to the measured data. In structures with low myelin content, such as deep gray matter, R2* shows a linear increase with increasing iron content. In white matter, R2* is not only affected by iron and myelin but also by the orientation of the myelinated axons with respect to the external magnetic field. Here, we propose a numerical model which incorporates iron and myelin, as well as fibre orientation, to simulate R2* decay in white matter. Applying our model to fibre orientation-dependent in vivo R2* data, we are able to determine a unique solution of myelin and iron content in global white matter. We determine an averaged myelin volume fraction of 16.02 ± 2.07% in non-lesional white matter of patients with MS, 17.32 ± 2.20% in matched healthy controls, and 18.19 ± 2.98% in healthy siblings of patients with MS. Averaged iron content was 35.6 ± 8.9 mg/kg tissue in patients, 43.1 ± 8.3 mg/kg in controls, and 47.8 ± 8.2 mg/kg in siblings. All differences in iron content between groups were significant, while the difference in myelin content between MS patients and the siblings of MS patients was significant. In conclusion, we demonstrate that a model that combines myelin-induced orientation-dependent and iron-induced orientation-independent components is able to fit in vivo R2* data.
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Affiliation(s)
- Daniel Kor
- Department of Physics & Astronomy, University of British Columbia, Vancouver, BC, Canada
- UBC MRI Research Centre, University of British Columbia, Vancouver, BC, Canada
| | - Christoph Birkl
- UBC MRI Research Centre, University of British Columbia, Vancouver, BC, Canada
- Department of Pediatrics (Division of Neurology), University of British Columbia, Vancouver, BC, Canada
- Department of Neurology, Medical University of Graz, Graz, Austria
| | - Stefan Ropele
- Department of Neurology, Medical University of Graz, Graz, Austria
| | - Jonathan Doucette
- Department of Physics & Astronomy, University of British Columbia, Vancouver, BC, Canada
- UBC MRI Research Centre, University of British Columbia, Vancouver, BC, Canada
- Department of Pediatrics (Division of Neurology), University of British Columbia, Vancouver, BC, Canada
| | - Tianyou Xu
- Oxford Centre for Functional MRI of the Brain, University of Oxford, Oxford, UK
| | - Vanessa Wiggermann
- Department of Physics & Astronomy, University of British Columbia, Vancouver, BC, Canada
- UBC MRI Research Centre, University of British Columbia, Vancouver, BC, Canada
- Department of Pediatrics (Division of Neurology), University of British Columbia, Vancouver, BC, Canada
| | - Enedino Hernández-Torres
- UBC MRI Research Centre, University of British Columbia, Vancouver, BC, Canada
- Department of Pediatrics (Division of Neurology), University of British Columbia, Vancouver, BC, Canada
| | - Simon Hametner
- Institute of Neuropathology, University Medical Center Göttingen, Göttingen, Germany
| | - Alexander Rauscher
- Department of Physics & Astronomy, University of British Columbia, Vancouver, BC, Canada
- UBC MRI Research Centre, University of British Columbia, Vancouver, BC, Canada
- Department of Pediatrics (Division of Neurology), University of British Columbia, Vancouver, BC, Canada
- Department of Radiology, University of British Columbia, Vancouver, BC, Canada
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Seifert AC, Umphlett M, Hefti M, Fowkes M, Xu J. Formalin tissue fixation biases myelin-sensitive MRI. Magn Reson Med 2019; 82:1504-1517. [PMID: 31125149 DOI: 10.1002/mrm.27821] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 04/29/2019] [Accepted: 04/30/2019] [Indexed: 12/20/2022]
Abstract
PURPOSE Chemical fixatives such as formalin form cross-links between proteins and affect the relaxation times and diffusion properties of tissue. These fixation-induced changes likely also affect myelin density measurements produced by quantitative magnetization transfer and myelin water imaging. In this work, we evaluate these myelin-sensitive MRI methods for fixation-induced biases. METHODS We perform quantitative magnetization transfer, myelin water imaging, and deuterium oxide-exchanged zero TE imaging on unfixed human spinal cord tissue at 9.4 Tesla and repeat these measurements after 1 day and 31 days of formalin fixation. RESULTS The quantitative magnetization-transfer bound pool fraction increased by 30.7% ± 21.1% after 1 day of fixation and by 42.6% ± 33.9% after 31 days of fixation. Myelin water fraction increased by 39.7% ± 15.5% and 37.0% ± 15.9% at these same time points, and mean T2 of the myelin water pool nearly doubled. Reference-normalized deuterium oxide-exchanged zero TE signal intensity increased by 8.17% ± 6.03% after 31 days of fixation but did not change significantly after 1 day of fixation. After fixation, specimen cross-sectional area decreased by approximately 5%; after correction for shrinkage, changes in deuterium oxide-exchanged zero TE intensity were nearly eliminated. CONCLUSION Bound pool fraction and myelin water fraction are significantly increased by formalin fixation, whereas deuterium oxide-exchanged zero TE intensity is minimally affected. Changes in quantitative magnetization transfer and myelin water imaging may be due in part to delamination and formation of vacuoles in the myelin sheath. Deuterium oxide-exchanged signal intensity may be altered by fixation-induced changes in myelin lipid solid-state 1 H T1 . We urge caution in the comparison of these measurements across subjects or specimens in different states, especially unfixed versus fixed tissue.
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Affiliation(s)
- Alan C Seifert
- Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, NY.,Department of Radiology, Icahn School of Medicine at Mount Sinai, New York, NY.,Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Melissa Umphlett
- Department of Pathology, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Marco Hefti
- Department of Pathology, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Mary Fowkes
- Department of Pathology, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Junqian Xu
- Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, NY.,Department of Radiology, Icahn School of Medicine at Mount Sinai, New York, NY.,Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY.,Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY
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Uddin MN, Figley TD, Solar KG, Shatil AS, Figley CR. Comparisons between multi-component myelin water fraction, T1w/T2w ratio, and diffusion tensor imaging measures in healthy human brain structures. Sci Rep 2019; 9:2500. [PMID: 30792440 DOI: 10.1038/s41598-019-39199-x] [Citation(s) in RCA: 69] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Accepted: 01/18/2019] [Indexed: 01/13/2023] Open
Abstract
Various MRI techniques, including myelin water imaging, T1w/T2w ratio mapping and diffusion-based imaging can be used to characterize tissue microstructure. However, surprisingly few studies have examined the degree to which these MRI measures are related within and between various brain regions. Therefore, whole-brain MRI scans were acquired from 31 neurologically-healthy participants to empirically measure and compare myelin water fraction (MWF), T1w/T2w ratio, fractional anisotropy (FA), axial diffusivity (AD), radial diffusivity (RD) and mean diffusivity (MD) in 25 bilateral (10 grey matter; 15 white matter) regions-of-interest (ROIs). Except for RD vs. T1w/T2w, MD vs. T1w/T2w, moderately significant to highly significant correlations (p < 0.001) were found between each of the other measures across all 25 brain structures [T1w/T2w vs. MWF (Pearson r = 0.33, Spearman ρ = 0.31), FA vs. MWF (r = 0.73, ρ = 0.75), FA vs. T1w/T2w (r = 0.25, ρ = 0.22), MD vs. AD (r = 0.57, ρ = 0.58), MD vs. RD (r = 0.64, ρ = 0.61), AD vs. MWF (r = 0.43, ρ = 0.36), RD vs. MWF (r = −0.49, ρ = −0.62), MD vs. MWF (r = −0.22, ρ = −0.29), RD vs. FA (r = −0.62, ρ = −0.75) and MD vs. FA (r = −0.22, ρ = −0.18)]. However, while all six MRI measures were correlated with each other across all structures, there were large intra-ROI and inter-ROI differences (i.e., with no one measure consistently producing the highest or lowest values). This suggests that each quantitative MRI measure provides unique, and potentially complimentary, information about underlying brain tissues – with each metric offering unique sensitivity/specificity tradeoffs to different microstructural properties (e.g., myelin content, tissue density, etc.).
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20
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Uddin MN, Figley TD, Figley CR. Effect of echo time and T2-weighting on GRASE-based T1w/T2w ratio measurements at 3T. Magn Reson Imaging 2018; 51:35-43. [DOI: 10.1016/j.mri.2018.04.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Revised: 04/17/2018] [Accepted: 04/18/2018] [Indexed: 12/24/2022]
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21
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Kumar D, Hariharan H, Faizy TD, Borchert P, Siemonsen S, Fiehler J, Reddy R, Sedlacik J. Using 3D spatial correlations to improve the noise robustness of multi component analysis of 3D multi echo quantitative T2 relaxometry data. Neuroimage 2018; 178:583-601. [PMID: 29763672 DOI: 10.1016/j.neuroimage.2018.05.026] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Revised: 05/07/2018] [Accepted: 05/08/2018] [Indexed: 12/18/2022] Open
Abstract
PURPOSE We present a computationally feasible and iterative multi-voxel spatially regularized algorithm for myelin water fraction (MWF) reconstruction. This method utilizes 3D spatial correlations present in anatomical/pathological tissues and underlying B1+-inhomogeneity or flip angle inhomogeneity to enhance the noise robustness of the reconstruction while intrinsically accounting for stimulated echo contributions using T2-distribution data alone. METHODS Simulated data and in vivo data acquired using 3D non-selective multi-echo spin echo (3DNS-MESE) were used to compare the reconstruction quality of the proposed approach against those of the popular algorithm (the method by Prasloski et al.) and our previously proposed 2D multi-slice spatial regularization spatial regularization approach. We also investigated whether the inter-sequence correlations and agreements improved as a result of the proposed approach. MWF-quantifications from two sequences, 3DNS-MESE vs 3DNS-gradient and spin echo (3DNS-GRASE), were compared for both reconstruction approaches to assess correlations and agreements between inter-sequence MWF-value pairs. MWF values from whole-brain data of six volunteers and two multiple sclerosis patients are being reported as well. RESULTS In comparison with competing approaches such as Prasloski's method or our previously proposed 2D multi-slice spatial regularization method, the proposed method showed better agreements with simulated truths using regression analyses and Bland-Altman analyses. For 3DNS-MESE data, MWF-maps reconstructed using the proposed algorithm provided better depictions of white matter structures in subcortical areas adjoining gray matter which agreed more closely with corresponding contrasts on T2-weighted images than MWF-maps reconstructed with the method by Prasloski et al. We also achieved a higher level of correlations and agreements between inter-sequence (3DNS-MESE vs 3DNS-GRASE) MWF-value pairs. CONCLUSION The proposed algorithm provides more noise-robust fits to T2-decay data and improves MWF-quantifications in white matter structures especially in the sub-cortical white matter and major white matter tract regions.
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22
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Stankoff B, Jadasz JJ, Hartung HP, Küry P, Zalc B, Lubetzki C. Repair strategies for multiple sclerosis: challenges, achievements and perspectives. Curr Opin Neurol 2016; 29:286-92. [PMID: 27035897 DOI: 10.1097/WCO.0000000000000325] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
PURPOSE OF REVIEW Despite major progress in multiple sclerosis (MS) treatment, to date, accumulation of irreversible clinical disability is not sufficiently prevented with immunotherapies. In this context, repair strategies aimed at reducing axonal damage are becoming a very active field of preclinical and clinical research. RECENT FINDINGS Improved understanding of the cellular and molecular mechanisms of myelin repair, together with the emergence of new therapeutic candidates are paving the way for novel therapeutic strategies in MS. In parallel, there is a very active development of imaging methods to assess lesions ongoing remyelination that are crucially needed to evaluate therapeutic efficacy. SUMMARY The current development of a very dynamic and multidisciplinary research on remyelination should accelerate the development of myelin repair strategies in MS, to prevent disability progression.
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Abstract
Myelin water imaging (MWI) provides mild traumatic brain injury (mTBI) researchers with a specific myelin biomarker and helps to further elucidate microstructural and microarchitectural changes of white matter after mTBI. Improvement of scanner hardware and software with the implementation of MWI across scanner platforms will likely result in increased research regarding the role of myelin in traumatic brain injury (TBI). Future research should include detailed investigation of myelin between 2 weeks and 2 months after injury, the use of MWI in moderate and severe TBI, and investigation of the role of myelin in chronic TBI.
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Affiliation(s)
- Alexander Mark Weber
- Department of Pediatrics, Division of Neurology, Faculty of Medicine, University of British Columbia, M10 - Purdy Pavilion, 2221 Wesbrook Mall, Vancouver, British Columbia V6T 2B5, Canada.
| | - Carlos Torres
- Department of Radiology, University of Ottawa, 1053 Carling Avenue, Ottawa, Ontario K1Y 4E9, Canada; Department of Medical Imaging, The Ottawa Hospital, 1053 Carling Avenue, Ottawa, Ontario K1Y 4E9, Canada
| | - Alexander Rauscher
- Department of Pediatrics, Division of Neurology, Faculty of Medicine, University of British Columbia, M10 - Purdy Pavilion, 2221 Wesbrook Mall, Vancouver, British Columbia V6T 2B5, Canada
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Jung W, Lee J, Shin HG, Nam Y, Zhang H, Oh SH, Lee J. Whole brain g-ratio mapping using myelin water imaging (MWI) and neurite orientation dispersion and density imaging (NODDI). Neuroimage 2017; 182:379-388. [PMID: 28962901 DOI: 10.1016/j.neuroimage.2017.09.053] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Revised: 08/23/2017] [Accepted: 09/24/2017] [Indexed: 10/18/2022] Open
Abstract
MR g-ratio, which measures the ratio of the aggregate volume of axons to that of fibers in a voxel, is a potential biomarker for white matter microstructures. In this study, a new approach for acquiring an in-vivo whole human brain g-ratio map is proposed. To estimate the g-ratio, myelin volume fraction and axonal volume fraction are acquired using multi-echo gradient echo myelin water imaging (GRE-MWI) and neurite orientation dispersion and density imaging (NODDI), respectively. In order to translate myelin water fraction measured in GRE-MWI into myelin volume fraction, a new scaling procedure is proposed and validated. This scaling approach utilizes geometric measures of myelin structure and, therefore, provides robustness over previous methods. The resulting g-ratio map reveals an expected range of g-ratios (0.71-0.85 in major fiber bundles) with a small inter-subject coefficient of variance (less than 2%). Additionally, a few fiber bundles (e.g. cortico-spinal tract and optic radiation) show different constituents of myelin volume fraction and axonal volume fraction, indicating potentials to utilize the measures for deciphering fiber tracking.
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Affiliation(s)
- Woojin Jung
- Laboratory for Imaging Science and Technology, Department of Electrical and Computer Engineering, Seoul National University, Seoul, South Korea
| | - Jingu Lee
- Laboratory for Imaging Science and Technology, Department of Electrical and Computer Engineering, Seoul National University, Seoul, South Korea
| | - Hyeong-Geol Shin
- Laboratory for Imaging Science and Technology, Department of Electrical and Computer Engineering, Seoul National University, Seoul, South Korea
| | - Yoonho Nam
- Department of Radiology, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, South Korea
| | - Hui Zhang
- Department of Computer Science & Centre for Medical Image Computing, University College London, London, United Kingdom
| | - Se-Hong Oh
- Division of Biomedical Engineering, Hankuk University of Foreign Studies, Yongin, South Korea
| | - Jongho Lee
- Laboratory for Imaging Science and Technology, Department of Electrical and Computer Engineering, Seoul National University, Seoul, South Korea.
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Chen HSM, Holmes N, Liu J, Tetzlaff W, Kozlowski P. Validating myelin water imaging with transmission electron microscopy in a rat spinal cord injury model. Neuroimage 2017; 153:122-130. [PMID: 28377211 DOI: 10.1016/j.neuroimage.2017.03.065] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 03/23/2017] [Accepted: 03/28/2017] [Indexed: 10/19/2022] Open
Abstract
Myelin content is an important marker for neuropathology and MRI generated myelin water fraction (MWF) has been shown to correlate well with myelin content. However, because MWF is based on the amount of signal from myelin water, that is, the water trapped between the myelin lipid bilayers, the reading may depend heavily on myelin morphology. This is of special concern when there is a mix of intact myelin and myelin debris, as in the case of injury. To investigate what MWF measures in the presence of debris, we compared MWF to transmission electron microscopy (TEM) derived myelin fraction that measures the amount of compact appearing myelin. A rat spinal cord injury model was used with time points at normal (normal myelin), 3 weeks post-injury (myelin debris), and 8 weeks post-injury (myelin debris, partially cleared). The myelin period between normal and 3 or 8 weeks post-injury cords did not differ significantly, suggesting that as long as the bilayer structure is intact, myelin debris has the same water content as intact myelin. The MWF also correlated strongly with the TEM-derived myelin fraction, suggesting that MWF measures the amount of compact appearing myelin in both intact myelin and myelin debris. From the TEM images, it appears that as myelin degenerates, it tends to form large watery spaces within the myelin sheaths that are not classified as myelin water. The results presented in this study improve our understanding and allows for better interpretation of MWF in the presence of myelin debris.
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Affiliation(s)
- Henry Szu-Meng Chen
- Department of Physics and Astronomy, University of British Columbia, Vancouver, Canada; University of British Columbia MRI Research Centre, Vancouver, Canada.
| | - Nathan Holmes
- International Collaboration on Repair Discoveries (ICORD), Vancouver, Canada; Department of Zoology, University of British Columbia, Vancouver, Canada
| | - Jie Liu
- International Collaboration on Repair Discoveries (ICORD), Vancouver, Canada.
| | - Wolfram Tetzlaff
- International Collaboration on Repair Discoveries (ICORD), Vancouver, Canada; Department of Zoology, University of British Columbia, Vancouver, Canada.
| | - Piotr Kozlowski
- University of British Columbia MRI Research Centre, Vancouver, Canada; International Collaboration on Repair Discoveries (ICORD), Vancouver, Canada; Department of Radiology, University of British Columbia, Vancouver, Canada.
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Meyers SM, Kolind SH, MacKay AL. Simultaneous measurement of total water content and myelin water fraction in brain at 3 T using a T 2 relaxation based method. Magn Reson Imaging 2017; 37:187-194. [DOI: 10.1016/j.mri.2016.12.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Revised: 11/05/2016] [Accepted: 12/01/2016] [Indexed: 01/19/2023]
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Puwal S, Roth BJ, Basser PJ. Heterogeneous anisotropic magnetic susceptibility of the myelin-water layers causes local magnetic field perturbations in axons. NMR Biomed 2017; 30:10.1002/nbm.3628. [PMID: 27731911 PMCID: PMC6130896 DOI: 10.1002/nbm.3628] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2015] [Revised: 06/23/2016] [Accepted: 08/17/2016] [Indexed: 05/23/2023]
Abstract
One goal of MRI is to determine the myelin water fraction in neural tissue. One approach is to measure the reduction in T2 * arising from microscopic perturbations in the magnetic field caused by heterogeneities in the magnetic susceptibility of myelin. In this paper, analytic expressions for the induced magnetic field distribution are derived within and around an axon, assuming that the myelin susceptibility is anisotropic. Previous models considered the susceptibility to be piecewise continuous, whereas this model considers a sinusoidally varying susceptibility. Many conclusions are common in both models. When the magnetic field is applied perpendicular to the axon, the magnetic field in the intraaxonal space is uniformly perturbed, the magnetic field in the myelin sheath oscillates between the lipid and water layers, and the magnetic field in the extracellular space just outside the myelin sheath is heterogeneous. These field heterogeneities cause the spins to dephase, shortening T2 *. When the magnetic field is applied along the axon, the field is homogeneous within water-filled regions, including between lipid layers. Therefore the spins do not dephase and the magnetic susceptibility has no effect on T2 *. Generally, the response of an axon is given as the superposition of these two contributions. The sinusoidal model uses a different set of approximations compared with the piecewise model, so their common predictions indicate that the models are not too sensitive to the details of the myelin-water distribution. Other predictions, such as the sensitivity to water diffusion between myelin and water layers, may highlight differences between the two approaches. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Steffan Puwal
- Department of Physics, Oakland University, Rochester, MI, USA
| | - Bradley J Roth
- Department of Physics, Oakland University, Rochester, MI, USA
| | - Peter J Basser
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
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Arshad M, Stanley JA, Raz N. Test-retest reliability and concurrent validity of in vivo myelin content indices: Myelin water fraction and calibrated T 1 w/T 2 w image ratio. Hum Brain Mapp 2016; 38:1780-1790. [PMID: 28009069 DOI: 10.1002/hbm.23481] [Citation(s) in RCA: 88] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 11/06/2016] [Accepted: 11/21/2016] [Indexed: 11/09/2022] Open
Abstract
In an age-heterogeneous sample of healthy adults, we examined test-retest reliability (with and without participant repositioning) of two popular MRI methods of estimating myelin content: modeling the short spin-spin (T2 ) relaxation component of multi-echo imaging data and computing the ratio of T1 -weighted and T2 -weighted images (T1 w/T2 w). Taking the myelin water fraction (MWF) index of myelin content derived from the multi-component T2 relaxation data as a standard, we evaluate the concurrent and differential validity of T1 w/T2 w ratio images. The results revealed high reliability of MWF and T1 w/T2 w ratio. However, we found significant correlations of low to moderate magnitude between MWF and the T1 w/T2 w ratio in only two of six examined regions of the cerebral white matter. Notably, significant correlations of the same or greater magnitude were observed for T1 w/T2 w ratio and the intermediate T2 relaxation time constant, which is believed to reflect differences in the mobility of water between the intracellular and extracellular compartments. We conclude that although both methods are highly reliable and thus well-suited for longitudinal studies, T1 w/T2 w ratio has low criterion validity and may be not an optimal index of subcortical myelin content. Hum Brain Mapp 38:1780-1790, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Muzamil Arshad
- Department of Psychiatry and Behavioral Neuroscience, School of Medicine, Wayne State University, Detroit, Michigan.,Institute of Gerontology, Wayne State University, Detroit, Michigan
| | - Jeffrey A Stanley
- Department of Psychiatry and Behavioral Neuroscience, School of Medicine, Wayne State University, Detroit, Michigan
| | - Naftali Raz
- Institute of Gerontology, Wayne State University, Detroit, Michigan.,Department of Psychology, Wayne State University, Detroit, Michigan
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Lakhani B, Borich MR, Jackson JN, Wadden KP, Peters S, Villamayor A, MacKay AL, Vavasour IM, Rauscher A, Boyd LA. Motor Skill Acquisition Promotes Human Brain Myelin Plasticity. Neural Plast 2016; 2016:7526135. [PMID: 27293906 DOI: 10.1155/2016/7526135] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Accepted: 04/20/2016] [Indexed: 12/21/2022] Open
Abstract
Experience-dependent structural changes are widely evident in gray matter. Using diffusion weighted imaging (DWI), the neuroplastic effect of motor training on white matter in the brain has been demonstrated. However, in humans it is not known whether specific features of white matter relate to motor skill acquisition or if these structural changes are associated to functional network connectivity. Myelin can be objectively quantified in vivo and used to index specific experience-dependent change. In the current study, seventeen healthy young adults completed ten sessions of visuomotor skill training (10,000 total movements) using the right arm. Multicomponent relaxation imaging was performed before and after training. Significant increases in myelin water fraction, a quantitative measure of myelin, were observed in task dependent brain regions (left intraparietal sulcus [IPS] and left parieto-occipital sulcus). In addition, the rate of motor skill acquisition and overall change in myelin water fraction in the left IPS were negatively related, suggesting that a slower rate of learning resulted in greater neuroplastic change. This study provides the first evidence for experience-dependent changes in myelin that are associated with changes in skilled movements in healthy young adults.
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Meyers SM, Kolind SH, Laule C, Mackay AL. Measuring water content using T2 relaxation at 3T: Phantom validations and simulations. Magn Reson Imaging 2016; 34:246-51. [DOI: 10.1016/j.mri.2015.11.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Revised: 07/23/2015] [Accepted: 11/29/2015] [Indexed: 12/14/2022]
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Wright AD, Jarrett M, Vavasour I, Shahinfard E, Kolind S, van Donkelaar P, Taunton J, Li D, Rauscher A. Myelin Water Fraction Is Transiently Reduced after a Single Mild Traumatic Brain Injury--A Prospective Cohort Study in Collegiate Hockey Players. PLoS One 2016; 11:e0150215. [PMID: 26913900 PMCID: PMC4767387 DOI: 10.1371/journal.pone.0150215] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Accepted: 02/10/2016] [Indexed: 12/12/2022] Open
Abstract
Impact-related mild traumatic brain injuries (mTBI) are a major public health concern, and remain as one of the most poorly understood injuries in the field of neuroscience. Currently, the diagnosis and management of such injuries are based largely on patient-reported symptoms. An improved understanding of the underlying pathophysiology of mTBI is urgently needed in order to develop better diagnostic and management protocols. Specifically, dynamic post-injury changes to the myelin sheath in the human brain have not been examined, despite ‘compromised white matter integrity’ often being described as a consequence of mTBI. In this preliminary cohort study, myelin water imaging was used to prospectively evaluate changes in myelin water fraction, derived from the T2 decay signal, in two varsity hockey teams (45 players) over one season of athletic competition. 11 players sustained a concussion during competition, and were scanned at 72 hours, 2 weeks, and 2 months post-injury. Results demonstrated a reduction in myelin water fraction at 2 weeks post-injury in several brain areas relative to preseason scans, including the splenium of the corpus callosum, right posterior thalamic radiation, left superior corona radiata, left superior longitudinal fasciculus, and left posterior limb of the internal capsule. Myelin water fraction recovered to pre-season values by 2 months post-injury. These results may indicate transient myelin disruption following a single mTBI, with subsequent remyelination of affected neurons. Myelin disruption was not apparent in the athletes who did not experience a concussion, despite exposure to repetitive subconcussive trauma over a season of collegiate hockey. These findings may help to explain many of the metabolic and neurological deficits observed clinically following mTBI.
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Affiliation(s)
- Alexander D. Wright
- MD/PhD Program, University of British Columbia, Vancouver, Canada
- Southern Medical Program, University of British Columbia Okanagan, Kelowna, Canada
- Department of Experimental Medicine, University of British Columbia, Vancouver, Canada
| | - Michael Jarrett
- UBC MRI Research Centre, University of British Columbia, Vancouver, Canada
| | - Irene Vavasour
- UBC MRI Research Centre, University of British Columbia, Vancouver, Canada
| | - Elham Shahinfard
- UBC MRI Research Centre, University of British Columbia, Vancouver, Canada
| | - Shannon Kolind
- Faculty of Medicine, Division of Neurology, University of British Columbia, Vancouver, Canada
| | - Paul van Donkelaar
- School of Health and Exercise Sciences, University of British Columbia Okanagan, Kelowna, Canada
| | - Jack Taunton
- Faculty of Medicine, Division of Sports Medicine, University of British Columbia, Vancouver, Canada
| | - David Li
- Faculty of Medicine, Department of Radiology, University of British Columbia, Vancouver, Canada
| | - Alexander Rauscher
- UBC MRI Research Centre, University of British Columbia, Vancouver, Canada
- Department of Pediatrics, Division of Neurology, University of British Columbia, Vancouver, Canada
- * E-mail:
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Akhondi-Asl A, Afacan O, Balasubramanian M, Mulkern RV, Warfield SK. Fast myelin water fraction estimation using 2D multislice CPMG. Magn Reson Med 2015; 76:1301-13. [PMID: 26536382 DOI: 10.1002/mrm.26034] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Revised: 09/22/2015] [Accepted: 10/15/2015] [Indexed: 11/09/2022]
Abstract
PURPOSE T2 relaxometry based on multiexponential fitting to a single slice multiecho sequence has been the most common MRI technique for myelin water fraction mapping, where the short T2 is associated with myelin water. However, very long acquisition times and physically unrealistic models for T2 distribution are limitations of this approach. We present a novel framework for myelin imaging which substantially increases the imaging speed and myelin water fraction estimation accuracy. METHOD We used the 2D multislice Carr-Purcell-Meiboom-Gill sequence to increase the volume coverage. To compensate for nonideal slice profiles, we numerically solved the Bloch equations for a range of T2 and B1 inhomogeneity scales to construct the bases for the estimation of the T2 distribution. We used a finite mixture of continuous parametric distributions to describe the complete T2 spectrum and used the constrained variable projection optimization algorithm to estimate myelin water fraction. To validate our model, synthetic, phantom, and in vivo brain experiments were conducted. RESULTS Using the Bloch equations, we can model the slice profile and construct the forward model of the T2 curve. Our method estimated myelin water fraction with smaller error than the nonnegative least squares algorithm. CONCLUSIONS The proposed framework can be used for reliable whole brain myelin imaging with a resolution of 2×2×4 mm3 in ≈17 min. Magn Reson Med 76:1301-1313, 2016. © 2015 Wiley Periodicals, Inc.
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Affiliation(s)
- Alireza Akhondi-Asl
- Computational Radiology Laboratory, Department of Radiology, Children's Hospital, Boston, Massachusetts, USA.
| | - Onur Afacan
- Computational Radiology Laboratory, Department of Radiology, Children's Hospital, Boston, Massachusetts, USA
| | - Mukund Balasubramanian
- Computational Radiology Laboratory, Department of Radiology, Children's Hospital, Boston, Massachusetts, USA
| | - Robert V Mulkern
- Computational Radiology Laboratory, Department of Radiology, Children's Hospital, Boston, Massachusetts, USA
| | - Simon K Warfield
- Computational Radiology Laboratory, Department of Radiology, Children's Hospital, Boston, Massachusetts, USA
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Vargas WS, Monohan E, Pandya S, Raj A, Vartanian T, Nguyen TD, Hurtado Rúa SM, Gauthier SA. Measuring longitudinal myelin water fraction in new multiple sclerosis lesions. Neuroimage Clin 2015; 9:369-75. [PMID: 26594620 PMCID: PMC4589846 DOI: 10.1016/j.nicl.2015.09.003] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Revised: 09/05/2015] [Accepted: 09/07/2015] [Indexed: 01/21/2023]
Abstract
Objectives Investigating the potential of myelin repair strategies in multiple sclerosis (MS) requires an understanding of myelin dynamics during lesion evolution. The objective of this study is to longitudinally measure myelin water fraction (MWF), an MRI biomarker of myelin, in new MS lesions and to identify factors that influence their subsequent myelin content. Methods Twenty-three MS patients were scanned with whole-brain Fast Acquisition with Spiral Trajectory and T2prep (FAST-T2) MWF mapping at baseline and median follow-up of 6 months. Eleven healthy controls (HC) confirmed the reproducibility of FAST-T2 in white matter regions of interests (ROIs) similar to a lesion size. A random-effect-model was implemented to determine the association between baseline clinical and lesion variables and the subsequent MWF. Results ROI-based measurements in HCs were highly correlated between scans [mean r = 0.893 (.764–.967)]. In MS patients, 38 gadolinium enhancing (Gd+) and 25 new non-enhancing (Gd−) T2 hyperintense lesions (5.7 months, ±3.8) were identified. Significant improvement in MWF was seen in Gd+ lesions (0.035 ± 0.029, p < 0.001) as compared to Gd− lesions (0.006 ± 0.017, p = 0.065). In the model, a higher baseline MWF (p < 0.001) and the presence of Gd (p < 0.001) were associated with higher subsequent MWF. Conclusions FAST T2 provides a clinically feasible method to quantify MWF in new MS lesions. The observed influence of baseline MWF, which represents a combined effect of both resolving edema and myelin change within acute lesions, suggests that the extent of initial inflammation impacts final myelin recovery. FAST-T2 can measure the extent of myelin loss within early MS lesions. The largest study utilizing an in-vivo MRI method to assess MS lesion change The majority of change occurs in the earliest stages after MS lesion development. The intensity of the acute inflammatory event is detrimental on MWF recovery.
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Affiliation(s)
- Wendy S. Vargas
- Department of Neurology, Weill Cornell Medical College, New York, NY, USA
- Corresponding author at: Department of Neurology, Multiple Sclerosis Center, Weill Cornell Medical College, Suite Y217, 1305 York Ave, New York, NY 10021, USA. Tel.: 646 962 3393; fax: 646 962 0390.Department of NeurologyMultiple Sclerosis CenterWeill Cornell Medical CollegeSuite Y2171305 York AveNew YorkNY10021USA
| | - Elizabeth Monohan
- Department of Neurology, Weill Cornell Medical College, New York, NY, USA
| | - Sneha Pandya
- Department of Radiology, Weill Cornell Medical College, New York, NY, USA
| | - Ashish Raj
- Feil Family Brain and Mind Research Institute, Weill Cornell Medical College, New York, NY, USA
- Department of Radiology, Weill Cornell Medical College, New York, NY, USA
| | - Timothy Vartanian
- Department of Neurology, Weill Cornell Medical College, New York, NY, USA
- Feil Family Brain and Mind Research Institute, Weill Cornell Medical College, New York, NY, USA
| | - Thanh D. Nguyen
- Department of Radiology, Weill Cornell Medical College, New York, NY, USA
| | | | - Susan A. Gauthier
- Department of Neurology, Weill Cornell Medical College, New York, NY, USA
- Feil Family Brain and Mind Research Institute, Weill Cornell Medical College, New York, NY, USA
- Corresponding author at: Department of Neurology, Multiple Sclerosis Center, Weill Cornell Medical College, Suite Y217, 1305 York Ave, New York, NY 10021, USA. Tel.: 646 962 3393; fax: 646 962 0390.Department of NeurologyMultiple Sclerosis CenterWeill Cornell Medical CollegeSuite Y2171305 York AveNew YorkNY10021USA
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Nguyen TD, Deh K, Monohan E, Pandya S, Spincemaille P, Raj A, Wang Y, Gauthier SA. Feasibility and reproducibility of whole brain myelin water mapping in 4 minutes using fast acquisition with spiral trajectory and adiabatic T2prep (FAST-T2) at 3T. Magn Reson Med 2015; 76:456-65. [PMID: 26331978 DOI: 10.1002/mrm.25877] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Revised: 06/17/2015] [Accepted: 07/07/2015] [Indexed: 11/12/2022]
Abstract
PURPOSE To develop and measure the reproducibility of 4-min whole brain myelin water fraction (MWF) mapping using fast acquisition with spiral trajectory and T2prep (FAST-T2) sequence at 3T. METHODS Experiments were performed on phantoms, 13 volunteers, and 16 patients with multiple sclerosis. MWF maps were extracted using a spatially constrained non-linear algorithm. The proposed adiabatic modified BIR-4 (mBIR-4) T2prep was compared with the conventional composite T2prep (COMP). The effect of reducing the number of echo times (TEs) from 15 to 6 (reducing scan time from 10 to 4 min) was evaluated. Reproducibility was assessed using correlation analysis, coefficient of variation (COV), and Bland-Altman plots. RESULTS Compared with COMP, mBIR-4 provided more accurate T2 in phantoms and better MWF maps in human brains. Reducing the number of TEs had a negligible effect on MWF map quality, with a regional MWF difference of <0.8%. Regional MWFs obtained by repeated scans showed excellent correlation (R = 0.99), low COV (1.3%-2.4%), and negligible bias within ±1% limits of agreement. On a voxel-wise basis, the agreement remained strong (correlation R = 0.89 ± 0.03, bias = 0.01% ± 0.29%, limits of agreement = [-3.35% ± 0.73%, 3.33% ± 0.61%]). CONCLUSION Whole brain MWF mapping with adiabatic FAST-T2 is feasible in 4 min and provides good intrasite reproducibility. Magn Reson Med 76:456-465, 2016. © 2015 Wiley Periodicals, Inc.
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Affiliation(s)
- Thanh D Nguyen
- Department of Radiology, Weill Cornell Medical College, New York, New York, USA
| | - Kofi Deh
- Department of Radiology, Weill Cornell Medical College, New York, New York, USA
| | - Elizabeth Monohan
- Department of Neurology and Neuroscience, Weill Cornell Medical College, New York, New York, USA
| | - Sneha Pandya
- Department of Radiology, Weill Cornell Medical College, New York, New York, USA
| | - Pascal Spincemaille
- Department of Radiology, Weill Cornell Medical College, New York, New York, USA
| | - Ashish Raj
- Department of Radiology, Weill Cornell Medical College, New York, New York, USA
| | - Yi Wang
- Department of Radiology, Weill Cornell Medical College, New York, New York, USA
| | - Susan A Gauthier
- Department of Neurology and Neuroscience, Weill Cornell Medical College, New York, New York, USA
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Ali TS, Bjarnason TA, Senger DL, Dunn JF, Joseph JT, Mitchell JR. QuantitativeT2: interactive quantitative T2 MRI witnessed in mouse glioblastoma. J Med Imaging (Bellingham) 2015. [PMID: 26213695 DOI: 10.1117/1.jmi.2.3.036002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The aim of this study was to establish an advanced analytical platform for complex in vivo pathologies. We have developed a software program, QuantitativeT2, for voxel-based real-time quantitative T2 magnetic resonance imaging. We analyzed murine brain tumors to confirm feasibility of our method for neurological conditions. Anesthetized mice (with invasive gliomas, and controls) were imaged on a 9.4 Tesla scanner using a Carr-Purcell-Meiboom-Gill sequence. The multiecho T2 decays from axial brain slices were analyzed using QuantitativeT2. T2 distribution histograms demonstrated substantial characteristic differences between normal and pathological brain tissues. Voxel-based quantitative maps of tissue water fraction (WF) and geometric mean T2 (gmT2) revealed the heterogeneous alterations to water compartmentalization caused by pathology. The numeric distribution of WF and gmT2 indicated the extent of tumor infiltration. Relative evaluations between in vivo scans and ex vivo histology indicated that the T2s between 30 and 150 ms were related to cellular density and the integrity of the extracellular matrix. Overall, QuantitativeT2 has demonstrated significant advancements in qT2 analysis with real-time operation. It is interactive with an intuitive workflow; can analyze data from many MR manufacturers; and is released as open-source code to encourage examination, improvement, and expansion of this method.
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Affiliation(s)
- Tonima Sumya Ali
- Queensland University of Technology , Science and Engineering Faculty, Department of Biomedical Engineering and Medical Physics, 2 George Street, Brisbane, QLD 4000, Australia
| | - Thorarin Albert Bjarnason
- Diagnostic Imaging Services , Interior Health, 101-3330 Richter Street, Kelowna V1W 4V5, Canada ; University of British Columbia , Department of Radiology, 2329 W Mall, Vancouver V6T 1Z4, Canada ; University of British Columbia Okanagan , 3333 University Way, Kelowna V1V 1V7, Canada
| | - Donna L Senger
- University of Calgary , Faculty of Medicine, Department of Oncology, 2500 University Drive, Calgary T2N 1N4, Canada
| | - Jeff F Dunn
- University of Calgary , Faculty of Medicine, Hotchkiss Brain Institute, 3330 Hospital Drive, Calgary T2N 4N1, Canada ; University of Calgary , Faculty of Medicine, Department of Radiology, 2500 University Drive, Calgary T2N 1N4, Canada
| | - Jeffery T Joseph
- Foothills Medical Centre , Department of Pathology, 1403 29 Street, Calgary T2N 2T9, Canada
| | - Joseph Ross Mitchell
- Mayo Clinic College of Medicine , Department of Radiology, 200 1st Street, Rochester, Minnesota 55905, United States
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Bodini B, Louapre C, Stankoff B. Advanced imaging tools to investigate multiple sclerosis pathology. Presse Med 2015; 44:e159-67. [DOI: 10.1016/j.lpm.2015.02.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Accepted: 02/23/2015] [Indexed: 12/26/2022] Open
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Lang DJ, Yip E, MacKay AL, Thornton AE, Vila-Rodriguez F, MacEwan GW, Kopala LC, Smith GN, Laule C, MacRae CB, Honer WG. 48 echo T₂ myelin imaging of white matter in first-episode schizophrenia: evidence for aberrant myelination. Neuroimage Clin 2014; 6:408-14. [PMID: 25379454 PMCID: PMC4218939 DOI: 10.1016/j.nicl.2014.10.006] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Revised: 09/27/2014] [Accepted: 10/11/2014] [Indexed: 11/20/2022]
Abstract
Myelin water imaging provides a novel strategy to assess myelin integrity and corresponding clinical relationships in psychosis, of particular relevance in frontal white matter regions. In the current study, T2 myelin water imaging was used to assess the myelin water fraction (MWF) signal from frontal areas in a sample of 58 individuals experiencing first-episode psychosis (FEP) and 44 healthy volunteers. No differences in frontal MWF were observed between FEP subjects and healthy volunteers; however, differences in normal patterns of associations between frontal MWF and age, education and IQ were seen. Significant positive relationships between frontal MWF and age, North American Adult Reading Test (NAART) IQ, and years of completed education were observed in healthy volunteers. In contrast, only the relationship between frontal MWF and NAART IQ was significant after Bonferroni correction in the FEP group. Additionally, significant positive relationships between age and MWF in the anterior and posterior internal capsules, the genu, and the splenium were observed in healthy volunteers. In FEP subjects, only the relationship between age and MWF in the splenium was statistically significant. Frontal MWF was not associated with local white matter volume. Altered patterns of association between age, years of education, and MWF in FEP suggest that subtle disturbances in myelination may be present early in the course of psychosis.
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Affiliation(s)
- Donna J.M. Lang
- Dept. Radiology, University of British Columbia, Vancouver, BC V5Z 4H4, Canada
| | - Eugene Yip
- Dept. Oncology, Medical Physics, University of Alberta, Edmonton, Alta T6G 1Z2, Canada
| | - Alexander L. MacKay
- Dept. Radiology, University of British Columbia, Vancouver, BC V5Z 4H4, Canada
| | - Allen E. Thornton
- Dept. Psychology, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
| | | | - G. William MacEwan
- Dept. Psychiatry, University of British Columbia, Vancouver, BC V5Z 4H4, Canada
| | - Lili C. Kopala
- Dept. Psychiatry, University of British Columbia, Vancouver, BC V5Z 4H4, Canada
| | - Geoffrey N. Smith
- Dept. Psychiatry, University of British Columbia, Vancouver, BC V5Z 4H4, Canada
| | - Cornelia Laule
- Dept. Radiology, University of British Columbia, Vancouver, BC V5Z 4H4, Canada
| | - Cassie B. MacRae
- Dept. Radiology, University of British Columbia, Vancouver, BC V5Z 4H4, Canada
| | - William G. Honer
- Dept. Psychiatry, University of British Columbia, Vancouver, BC V5Z 4H4, Canada
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Bouhrara M, Reiter DA, Spencer RG. Bayesian analysis of transverse signal decay with application to human brain. Magn Reson Med 2014; 74:785-802. [PMID: 25242062 DOI: 10.1002/mrm.25457] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Revised: 08/23/2014] [Accepted: 08/24/2014] [Indexed: 12/20/2022]
Abstract
PURPOSE Transverse relaxation analysis with several signal models has been used extensively to determine tissue and material properties. However, the derivation of corresponding parameter values is notoriously unreliable. We evaluate improvements in the quality of parameter estimation using Bayesian analysis and incorporating the Rician noise model, as appropriate for magnitude MR images. THEORY AND METHODS Monoexponential, stretched exponential, and biexponential signal models were analyzed using nonlinear least squares (NLLS) and Bayesian approaches. Simulations and phantom and human brain data were analyzed using three different approaches to account for noise. Parameter estimation bias (reflecting accuracy) and dispersion (reflecting precision) were derived for a range of signal-to-noise ratios (SNR) and relaxation parameters. RESULTS All methods performed well at high SNR. At lower SNR, the Bayesian approach yielded parameter estimates of considerably greater precision, as well as greater accuracy, than did NLLS. Incorporation of the Rician noise model greatly improved accuracy and, to a somewhat lesser extent, precision, in derived transverse relaxation parameters. Analyses of data obtained from solution phantoms and from brain were consistent with simulations. CONCLUSION Overall, estimation of parameters characterizing several different transverse relaxation models was markedly improved through use of Bayesian analysis and through incorporation of the Rician noise model.
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Affiliation(s)
- Mustapha Bouhrara
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, USA
| | - David A Reiter
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, USA
| | - Richard G Spencer
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, USA
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Raj A, Pandya S, Shen X, LoCastro E, Nguyen TD, Gauthier SA. Multi-compartment T2 relaxometry using a spatially constrained multi-Gaussian model. PLoS One 2014; 9:e98391. [PMID: 24896833 PMCID: PMC4045663 DOI: 10.1371/journal.pone.0098391] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Accepted: 05/02/2014] [Indexed: 11/18/2022] Open
Abstract
The brain's myelin content can be mapped by T2-relaxometry, which resolves multiple differentially relaxing T2 pools from multi-echo MRI. Unfortunately, the conventional fitting procedure is a hard and numerically ill-posed problem. Consequently, the T2 distributions and myelin maps become very sensitive to noise and are frequently difficult to interpret diagnostically. Although regularization can improve stability, it is generally not adequate, particularly at relatively low signal to noise ratio (SNR) of around 100-200. The purpose of this study was to obtain a fitting algorithm which is able to overcome these difficulties and generate usable myelin maps from noisy acquisitions in a realistic scan time. To this end, we restrict the T2 distribution to only 3 distinct resolvable tissue compartments, modeled as Gaussians: myelin water, intra/extra-cellular water and a slow relaxing cerebrospinal fluid compartment. We also impose spatial smoothness expectation that volume fractions and T2 relaxation times of tissue compartments change smoothly within coherent brain regions. The method greatly improves robustness to noise, reduces spatial variations, improves definition of white matter fibers, and enhances detection of demyelinating lesions. Due to efficient design, the additional spatial aspect does not cause an increase in processing time. The proposed method was applied to fast spiral acquisitions on which conventional fitting gives uninterpretable results. While these fast acquisitions suffer from noise and inhomogeneity artifacts, our preliminary results indicate the potential of spatially constrained 3-pool T2 relaxometry.
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Affiliation(s)
- Ashish Raj
- Department of Radiology, Weill Cornell Medical College, New York, New York, United States of America
| | - Sneha Pandya
- Department of Radiology, Weill Cornell Medical College, New York, New York, United States of America
| | - Xiaobo Shen
- Department of Radiology, Weill Cornell Medical College, New York, New York, United States of America
| | - Eve LoCastro
- Department of Radiology, Weill Cornell Medical College, New York, New York, United States of America
| | - Thanh D. Nguyen
- Department of Radiology, Weill Cornell Medical College, New York, New York, United States of America
| | - Susan A. Gauthier
- Department of Neurology and Neuroscience, Weill Cornell Medical College, New York, New York, United States of America
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40
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Abstract
Demyelinating diseases such as multiple sclerosis cause changes in the brain white matter microstructure. Multi-exponential T2 relaxometry is a powerful technology for detecting these changes by generating a myelin water fraction (MWF) map. However, conventional approaches are subject to noise and spatial in-consistence. We proposed a novel approach by imposing spatial consistency and smoothness constraints. We first introduce a two-Gaussian model to approximate the T2 distribution. Then an expectation-maximization framework is introduced with an edge-preserving prior incorporated. Three-dimensional multi-echo MRI data sets were collected from three patients and three healthy volunteers. MWF maps obtained using the conventional, Spatially Regularized Non-negative Least Squares (srNNLS) algorithm as well as the proposed algorithm are compared. The proposed method provides MWF maps with improved depiction of brain structures and significantly lower coefficients of variance in various brain regions,
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41
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Meyers SM, Vavasour IM, Mädler B, Harris T, Fu E, Li DK, Traboulsee AL, MacKay AL, Laule C. Multicenter measurements of myelin water fraction and geometric mean T2: Intra- and intersite reproducibility. J Magn Reson Imaging 2013; 38:1445-53. [DOI: 10.1002/jmri.24106] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2012] [Accepted: 02/11/2013] [Indexed: 11/10/2022] Open
Affiliation(s)
- Sandra M. Meyers
- Physics and Astronomy; University of British Columbia; Vancouver BC Canada
| | | | | | - Trudy Harris
- UBC MRI Research Centre; University of British Columbia; Vancouver BC Canada
| | - Eric Fu
- Centre for Health Evaluation and Outcome Sciences; St Paul's Hospital; BC Canada
| | - David K.B. Li
- Radiology; University of British Columbia; Vancouver BC Canada
- UBC MRI Research Centre; University of British Columbia; Vancouver BC Canada
- Medicine, University of British Columbia; Vancouver BC Canada
| | | | - Alex L. MacKay
- Physics and Astronomy; University of British Columbia; Vancouver BC Canada
- Radiology; University of British Columbia; Vancouver BC Canada
- UBC MRI Research Centre; University of British Columbia; Vancouver BC Canada
| | - Cornelia Laule
- Radiology; University of British Columbia; Vancouver BC Canada
- UBC MRI Research Centre; University of British Columbia; Vancouver BC Canada
- Pathology and Laboratory Medicine; University of British Columbia; Vancouver BC Canada
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Laule C, Pavlova V, Leung E, Zhao G, MacKay AL, Kozlowski P, Traboulsee AL, Li DK, Moore GR. Diffusely abnormal white matter in multiple sclerosis: further histologic studies provide evidence for a primary lipid abnormality with neurodegeneration. J Neuropathol Exp Neurol 2013; 72:42-52. [PMID: 23242281 DOI: 10.1097/NEN.0b013e31827bced3] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Although multiple sclerosis (MS) lesions have been studied extensively using histology and magnetic resonance imaging (MRI), little is known about diffusely abnormal white matter (DAWM). Diffusely abnormal white matter, regions with reduced mild MRI hyperintensity and ill-defined boundaries, show reduced myelin water fraction, and decreased Luxol fast blue staining of myelin phospholipids, with relative preservation of myelin basic protein and 2',3'-cyclic-nucleotide 3'-phosphohydrolase. Because DAWM may be important in MS disability and progression, further histologic characterization is warranted. The MRI data were collected on 14 formalin-fixed MS brain samples that were then stained for myelin phospholipids, myelin proteins, astrocytes and axons. Diffusely abnormal white matter showed reduced myelin water fraction (-30%, p < 0.05 for 13 samples). Myelin phospholipids showed the most dramatic and consistent histologic reductions in staining optical density (-29% Luxol fast blue and -24% Weil's, p < 0.05 for 13 and 14 samples,respectively) with lesser myelin protein involvement (-11% myelin-associated glycoprotein, -10% myelin basic protein, -8% myelin-oligodendrocyte glycoprotein, -7% proteolipid protein, -5% 2',3'-cyclic-nucleotide 3'-phosphohydrolase, p < 0.05 for 3, 3, 1, 2, and 3 samples, respectively). Axonal involvement was intermediate. Diffusely abnormal white matter lipid and protein reductions occurred independently. These findings suggest a primary lipid abnormality in DAWM that exceeds protein loss and is accompanied by axonal degeneration. These phenomena may be important in MS pathogenesis and disease progression, which is prominent in individuals with DAWM.
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43
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Deoni SCL, Matthews L, Kolind SH. One component? Two components? Three? The effect of including a nonexchanging "free" water component in multicomponent driven equilibrium single pulse observation of T1 and T2. Magn Reson Med 2012; 70:147-54. [PMID: 22915316 DOI: 10.1002/mrm.24429] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2012] [Revised: 06/28/2012] [Accepted: 06/30/2012] [Indexed: 11/08/2022]
Abstract
Quantitative myelin content imaging provides novel and pertinent information related to underlying pathogenetic mechanisms of myelin-related disease or disorders arising from aberrant connectivity. Multicomponent driven equilibrium single pulse observation of T1 and T2 is a time-efficient multicomponent relaxation analysis technique that provides estimates of the myelin water fraction, a surrogate measure of myelin volume. Unfortunately, multicomponent driven equilibrium single pulse observation of T1 and T2 relies on a two water-pool model (myelin-associated water and intra/extracellular water), which is inadequate within partial volume voxels, i.e., containing brain tissue and ventricle or meninges, resulting in myelin water fraction underestimation. To address this, a third, nonexchanging "free-water" component was introduced to the multicomponent driven equilibrium single pulse observation of T1 and T2 model. Numerical simulations and experimental in vivo data show that the model to perform advantageously within partial volume regions while providing robust and reproducible results. It is concluded that this model is preferable for future studies and analysis.
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Affiliation(s)
- Sean C L Deoni
- Advanced Baby Imaging Lab, School of Engineering, Brown University, Providence, Rhode Island 02912, USA.
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44
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Tonkova V, Arhelger V, Schenk J, Neeb H. Rapid myelin water content mapping on clinical MR systems. Z Med Phys 2012; 22:133-42. [DOI: 10.1016/j.zemedi.2011.09.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2011] [Revised: 09/18/2011] [Accepted: 09/19/2011] [Indexed: 10/15/2022]
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45
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Kumar D, Nguyen TD, Gauthier SA, Raj A. Bayesian algorithm using spatial priors for multiexponential T₂ relaxometry from multiecho spin echo MRI. Magn Reson Med 2012; 68:1536-43. [PMID: 22266707 DOI: 10.1002/mrm.24170] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2011] [Revised: 11/29/2011] [Accepted: 12/21/2011] [Indexed: 12/19/2022]
Abstract
Multiexponential T₂ relaxometry is a powerful research tool for detecting brain structural changes due to demyelinating diseases such as multiple sclerosis. However, because of unusually high signal-to-noise ratio requirement compared with other MR modalities and ill-posedness of the underlying inverse problem, the T₂ distributions obtained with conventional approaches are frequently prone to noise effects. In this article, a novel multivoxel Bayesian algorithm using spatial prior information is proposed. This prior takes into account the expectation that volume fractions and T₂ relaxation times of tissue compartments change smoothly within coherent brain regions. Three-dimensional multiecho spin echo MRI data were collected from five healthy volunteers at 1.5 T and myelin water fraction maps were obtained using the conventional and proposed algorithms. Compared with the conventional method, the proposed method provides myelin water fraction maps with improved depiction of brain structures and significantly lower coefficients of variance in white matter.
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Affiliation(s)
- Dushyant Kumar
- Department of Radiology, Weill Cornell Medical College, New York, New York, USA
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46
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Garcia M, Gloor M, Radue E, Stippich C, Wetzel S, Scheffler K, Bieri O. Fast high-resolution brain imaging with balanced SSFP: Interpretation of quantitative magnetization transfer towards simple MTR. Neuroimage 2012; 59:202-11. [DOI: 10.1016/j.neuroimage.2011.07.038] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2011] [Accepted: 07/12/2011] [Indexed: 11/17/2022] Open
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47
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Kitzler HH, Su J, Zeineh M, Harper-Little C, Leung A, Kremenchutzky M, Deoni SC, Rutt BK. Deficient MWF mapping in multiple sclerosis using 3D whole-brain multi-component relaxation MRI. Neuroimage 2011; 59:2670-7. [PMID: 21920444 DOI: 10.1016/j.neuroimage.2011.08.052] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2011] [Revised: 08/16/2011] [Accepted: 08/18/2011] [Indexed: 12/14/2022] Open
Abstract
Recent multiple sclerosis (MS) MRI research has highlighted the need to move beyond the lesion-centric view and to develop and validate new MR imaging strategies that quantify the invisible burden of disease in the brain and establish much more sensitive and specific surrogate markers of clinical disability. One of the most promising of such measures is myelin-selective MRI that allows the acquisition of myelin water fraction (MWF) maps, a parameter that is correlated to brain white matter (WM) myelination. The aim of our study was to apply the newest myelin-selective MRI method, multi-component Driven Equilibrium Single Pulse Observation of T1 and T2 (mcDESPOT) in a controlled clinical MS pilot trial. This study was designed to assess the capabilities of this new method to explain differences in disease course and degree of disability in subjects spanning a broad spectrum of MS disease severity. The whole-brain isotropically-resolved 3D acquisition capability of mcDESPOT allowed for the first time the registration of 3D MWF maps to standard space, and consequently a formalized voxel-based analysis of the data. This approach combined with image segmentation further allowed the derivation of new measures of MWF deficiency: total deficient MWF volume (DV) in WM, in WM lesions, in diffusely abnormal white matter and in normal appearing white matter (NAWM). Deficient MWF volume fraction (DVF) was derived from each of these by dividing by the corresponding region volume. Our results confirm that lesion burden does not correlate well with clinical disease activity measured with the extended disability status scale (EDSS) in MS patients. In contrast, our measurements of DVF in NAWM correlated significantly with the EDSS score (R2=0.37; p<0.001). The same quantity discriminated clinically isolated syndrome patients from a normal control population (p<0.001) and discriminated relapsing-remitting from secondary-progressive patients (p<0.05); hence this new technique may sense early disease-related myelin loss and transitions to progressive disease. Multivariate analysis revealed that global atrophy, mean whole-brain myelin water fraction and white matter atrophy were the three most important image-derived parameters for predicting clinical disability (EDSS). Overall, our results demonstrate that mcDESPOT-defined measurements in NAWM show great promise as imaging markers of global clinical disease activity in MS. Further investigation will determine if this measure can serve as a risk factor for the conversion into definite MS and for the secondary transition into irreversible disease progression.
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Affiliation(s)
- Hagen H Kitzler
- Department of Neuroadiology, University Hospital Carl Gustav Carus, Technische Universität Dresden, Fetscherstr. 74, 01307 Dresden, Germany.
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48
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Hwang D, Chung H, Nam Y, Du YP, Jang U. Robust mapping of the myelin water fraction in the presence of noise: Synergic combination of anisotropic diffusion filter and spatially regularized nonnegative least squares algorithm. J Magn Reson Imaging 2011; 34:189-95. [PMID: 21618330 DOI: 10.1002/jmri.22586] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2010] [Accepted: 03/04/2011] [Indexed: 11/07/2022] Open
Affiliation(s)
- Dosik Hwang
- School of Electrical and Electronic Engineering, Yonsei University, Seoul, Korea.
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49
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Abstract
A quarter-century ago visual neuroscientists had little information about the number and organization of retinotopic maps in human visual cortex. The advent of functional magnetic resonance imaging (MRI), a non-invasive, spatially-resolved technique for measuring brain activity, provided a wealth of data about human retinotopic maps. Just as there are differences amongst non-human primate maps, the human maps have their own unique properties. Many human maps can be measured reliably in individual subjects during experimental sessions lasting less than an hour. The efficiency of the measurements and the relatively large amplitude of functional MRI signals in visual cortex make it possible to develop quantitative models of functional responses within specific maps in individual subjects. During this last quarter-century, there has also been significant progress in measuring properties of the human brain at a range of length and time scales, including white matter pathways, macroscopic properties of gray and white matter, and cellular and molecular tissue properties. We hope the next 25years will see a great deal of work that aims to integrate these data by modeling the network of visual signals. We do not know what such theories will look like, but the characterization of human retinotopic maps from the last 25years is likely to be an important part of future ideas about visual computations.
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Affiliation(s)
- Brian A Wandell
- Psychology Department, Stanford University, Stanford, CA 94305, United States.
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50
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MacMillan EL, Mädler B, Fichtner N, Dvorak MF, Li DK, Curt A, MacKay AL. Myelin water and T(2) relaxation measurements in the healthy cervical spinal cord at 3.0T: repeatability and changes with age. Neuroimage 2011; 54:1083-90. [PMID: 20832480 DOI: 10.1016/j.neuroimage.2010.08.076] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2010] [Revised: 08/22/2010] [Accepted: 08/31/2010] [Indexed: 11/23/2022] Open
Abstract
Multiecho T(2) relaxation measurements offer specific information about myelin content through the myelin water fraction (MWF), as well as about the water environments through the intra- and extra-cellular (IE), and global, geometric mean T(2) (GMT(2)) times. While these measurements have yielded new insights into brain development and pathologies, they have yet to be thoroughly investigated in the spinal cord. The goals of this study were: (1) to apply a new 3D multiecho T(2) relaxation measurement in the cervical spine with sufficient axial resolution to distinguish grey and white matter; (2) to perform a pilot reliability assessment of the resulting MWF and GMT(2) measures in a target population; and (3) to detect differences in these measures between a younger cohort (20-30 years of age) and an older cohort (50-75 years of age) of healthy adults. The results demonstrated that the MWF in younger healthy adults follows the known pattern of lower myelin content in grey matter (mean (95% confidence interval)) (0.049 (0.030-0.067)) as compared to white matter (0.296 (0.275-0.317), p<0.001). The reliability coefficients were 0.65 and 0.82 for the MWF in the dorsal (DC) and lateral column (LC) white matter, respectively; 0.79 and 0.52 for the IE GMT(2); and 0.74 and 0.73 for the global GMT(2). Significantly lower MWF were found in the older adults than in the younger adults (DC p=0.014; LC p=0.012), as well as lower IE GMT(2) times (DC p=0.008; LC p=0.042), however, the global GMT(2) times did not show any differences. These changes in MWF and IE GMT(2) times, but not in global GMT(2) times, indicate that multiecho T(2) relaxation measures are sensitive to changes in myelin integrity and cell morphology that may not be apparent on conventional T(2) weighted images.
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