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Autosomal dominant cerebellar ataxias: Imaging biomarkers with high effect sizes. NEUROIMAGE-CLINICAL 2018; 19:858-867. [PMID: 29922574 PMCID: PMC6005808 DOI: 10.1016/j.nicl.2018.06.011] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Revised: 05/19/2018] [Accepted: 06/07/2018] [Indexed: 12/13/2022]
Abstract
Objective As gene-based therapies may soon arise for patients with spinocerebellar ataxia (SCA), there is a critical need to identify biomarkers of disease progression with effect sizes greater than clinical scores, enabling trials with smaller sample sizes. Methods We enrolled a unique cohort of patients with SCA1 (n = 15), SCA2 (n = 12), SCA3 (n = 20) and SCA7 (n = 10) and 24 healthy controls of similar age, sex and body mass index. We collected longitudinal clinical and imaging data at baseline and follow-up (mean interval of 24 months). We performed both manual and automated volumetric analyses. Diffusion tensor imaging (DTI) and a novel tractography method, called fixel-based analysis (FBA), were assessed at follow-up. Effect sizes were calculated for clinical scores and imaging parameters. Results Clinical scores worsened as atrophy increased over time (p < 0.05). However, atrophy of cerebellum and pons showed very large effect sizes (>1.2) compared to clinical scores (<0.8). FBA, applied for the first time to SCA, was sensitive to microstructural cross-sectional differences that were not captured by conventional DTI metrics, especially in the less studied SCA7 group. FBA also showed larger effect sizes than DTI metrics. Conclusion This study showed that volumetry outperformed clinical scores to measure disease progression in SCA1, SCA2, SCA3 and SCA7. Therefore, we advocate the use of volumetric biomarkers in therapeutic trials of autosomal dominant ataxias. In addition, FBA showed larger effect size than DTI to detect cross-sectional microstructural alterations in patients relative to controls. Biomarkers are needed to test upcoming therapies for spinocerebellar ataxia. As spinocerebellar ataxias are rare, biomarkers with high effect sizes are needed. We identified imaging biomarkers with higher effect sizes than clinical scores.
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Key Words
- Apparent fiber density
- CCFS, composite cerebellar functional severity score
- CFE, connectivity-based fixel enhancement
- CSD, constrained spherical deconvolution
- CST, corticospinal tract
- DTI, diffusion tensor imaging
- Diffusion imaging.
- FA, fractional anisotropy
- FBA, fixel-based analysis
- FC, fiber cross-section
- FD, fiber density
- FDC, fiber density and cross-section
- FOD, fiber orientation distribution
- FOV, Field of view
- Fixel analysis
- GRAPPA, generalized autocalibrating partial parallel acquisition
- Imaging biomarkers
- MPRAGE, magnetization-prepared rapid gradient-echo
- MRI, magnetic resonance imaging
- RD, radial diffusivity
- SARA, scale for the assessment and rating of ataxia
- SCA, spinocerebellar ataxias
- SNR, signal-to-noise ratio
- Spinocerebellar ataxia
- TBSS, tract-based spatial statistics
- TE, echo time
- TR, repetition time
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Comparison of probabilistic tractography and tract-based spatial statistics for assessing optic radiation damage in patients with autoimmune inflammatory disorders of the central nervous system. NEUROIMAGE-CLINICAL 2018; 19:538-550. [PMID: 29984162 PMCID: PMC6029567 DOI: 10.1016/j.nicl.2018.05.004] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 05/03/2018] [Accepted: 05/06/2018] [Indexed: 10/28/2022]
Abstract
Background Diffusion Tensor Imaging (DTI) can evaluate microstructural tissue damage in the optic radiation (OR) of patients with clinically isolated syndrome (CIS), early relapsing-remitting multiple sclerosis and neuromyelitis optica spectrum disorders (NMOSD). Different post-processing techniques, e.g. tract-based spatial statistics (TBSS) and probabilistic tractography, exist to quantify this damage. Objective To evaluate the capacity of TBSS-based atlas region-of-interest (ROI) combination with 1) posterior thalamic radiation ROIs from the Johns Hopkins University atlas (JHU-TBSS), 2) Juelich Probabilistic ROIs (JUEL-TBSS) and tractography methods using 3) ConTrack (CON-PROB) and 4) constrained spherical deconvolution tractography (CSD-PROB) to detect OR damage in patients with a) NMOSD with prior ON (NMOSD-ON), b) CIS and early RRMS patients with ON (CIS/RRMS-ON) and c) CIS and early RRMS patients without prior ON (CIS/RRMS-NON) against healthy controls (HCs). Methods Twenty-three NMOSD-ON, 18 CIS/RRMS-ON, 21 CIS/RRMS-NON, and 26 HCs underwent 3 T MRI. DTI data analysis was carried out using JUEL-TBSS, JHU-TBSS, CON-PROB and CSD-PROB. Optical coherence tomography (OCT) and visual acuity testing was performed in the majority of patients and HCs. Results Absolute OR fractional anisotropy (FA) values differed between all methods but showed good correlation and agreement in Bland-Altman analysis. OR FA values between NMOSD and HC differed throughout the methodologies (p-values ranging from p < 0.0001 to 0.0043). ROC-analysis and effect size estimation revealed higher AUCs and R2 for CSD-PROB (AUC = 0.812; R2 = 0.282) and JHU-TBSS (AUC = 0.756; R2 = 0.262), compared to CON-PROB (AUC = 0.742; R2 = 0.179) and JUEL-TBSS (AUC = 0.719; R2 = 0.161). Differences between CIS/RRMS-NON and HC were only observable in CSD-PROB (AUC = 0.796; R2 = 0.094). No significant differences between CIS/RRMS-ON and HC were detected by any of the methods. Conclusions All DTI post-processing techniques facilitated the detection of OR damage in patient groups with severe microstructural OR degradation. The comparison of distinct disease groups by use of different methods may lead to different - either false-positive or false-negative - results. Since different DTI post-processing approaches seem to provide complementary information on OR damage, application of distinct methods may depend on the relevant research question.
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Key Words
- AD, axial diffusivity
- AUC, area under the curve
- CIS, clinically isolated syndrome
- CON, Contrack
- CSD, constrained spherical deconvolution
- DTI
- DTI, diffusion tensor imaging
- DW-MRI, diffusion weighted magnetic resonance imaging
- DWI, diffusion weighted imaging
- FA, fractional anisotropy
- FOD, fiber orientation distribution
- HC, Healthy Control
- JHU, Johns Hopkins University DTI white matter atlas
- JUEL, Juelich histological atlas
- LGN, lateral geniculate nucleus
- MD, mean diffusivity
- MS, multiple sclerosis
- Multiple sclerosis
- NMOSD, neuromyelitis optica spectrum disorder
- Neuromyelitis optica
- OCT, optical coherence tomography
- ON, optic neuritis
- OR, optic radiation
- Optic radiation
- PROB, probabilistic tractography
- Probabilistic tractography
- RD, radial diffusivity
- RNFL, retinal nerve fiber layer thickness
- ROC, receiver operating characteristic
- ROI, region of interest
- RRMS, relapsing-remitting multiple sclerosis
- SD, standard deviation
- SEM, standard error of the mean
- TBSS
- TBSS, tract-based spatial statistics
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Sex differences in white matter alterations following repetitive subconcussive head impacts in collegiate ice hockey players. NEUROIMAGE-CLINICAL 2017; 17:642-649. [PMID: 29204342 PMCID: PMC5709295 DOI: 10.1016/j.nicl.2017.11.020] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/29/2017] [Revised: 11/08/2017] [Accepted: 11/18/2017] [Indexed: 12/31/2022]
Abstract
Objective Repetitive subconcussive head impacts (RSHI) may lead to structural, functional, and metabolic alterations of the brain. While differences between males and females have already been suggested following a concussion, whether there are sex differences following exposure to RSHI remains unknown. The aim of this study was to identify and to characterize sex differences following exposure to RSHI. Methods Twenty-five collegiate ice hockey players (14 males and 11 females, 20.6 ± 2.0 years), all part of the Hockey Concussion Education Project (HCEP), underwent diffusion-weighted magnetic resonance imaging (dMRI) before and after the Canadian Interuniversity Sports (CIS) ice hockey season 2011-2012 and did not experience a concussion during the season. Whole-brain tract-based spatial statistics (TBSS) were used to compare pre- and postseason imaging in both sexes for fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD). Pre- and postseason neurocognitive performance were assessed by the Immediate Post-Concussion Assessment and Cognitive Test (ImPACT). Results Significant differences between the sexes were primarily located within the superior longitudinal fasciculus (SLF), the internal capsule (IC), and the corona radiata (CR) of the right hemisphere (RH). In significant voxel clusters (p < 0.05), decreases in FA (absolute difference pre- vs. postseason: 0.0268) and increases in MD (0.0002), AD (0.00008), and RD (0.00005) were observed in females whereas males showed no significant changes. There was no significant correlation between the change in diffusion scalar measures over the course of the season and neurocognitive performance as evidenced from postseason ImPACT scores. Conclusions The results of this study suggest sex differences in structural alterations following exposure to RSHI. Future studies need to investigate further the underlying mechanisms and association with exposure and clinical outcomes.
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Key Words
- AD, axial diffusivity
- CIS, Canadian Interuniversity Sports
- CR, corona radiata
- Diffusion tensor imaging
- EC, external capsule
- FA, fractional anisotropy
- HCEP, Hockey Concussion Education Project
- IC, internal capsule
- Ice hockey
- ImPACT, Immediate Post-Concussion Assessment and Cognitive Test
- LH, left hemisphere
- MD, mean diffusivity
- MRI, magnetic resonance imaging
- NCAA, National Collegiate Athletic Association
- RD, radial diffusivity
- RH, right hemisphere
- RSHI, repetitive subconcussive head impacts
- Repetitive subconcussive head impacts
- SD, standard deviation
- SLF, superior longitudinal fasciculus
- Sex difference
- TBI, traumatic brain injury
- TBSS, tract-based spatial statistics
- Traumatic brain injury
- WM, white matter
- White matter
- dMRI, diffusion magnetic resonance imaging
- rs, Spearman's rank correlation coefficient
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White matter alterations and their associations with motor function in young adults born preterm with very low birth weight. NEUROIMAGE-CLINICAL 2017; 17:241-250. [PMID: 29159041 PMCID: PMC5683190 DOI: 10.1016/j.nicl.2017.10.006] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Revised: 09/30/2017] [Accepted: 10/03/2017] [Indexed: 01/08/2023]
Abstract
Very low birth weight (VLBW: ≤ 1500 g) individuals have an increased risk of white matter alterations and neurodevelopmental problems, including fine and gross motor problems. In this hospital-based follow-up study, the main aim was to examine white matter microstructure and its relationship to fine and gross motor function in 31 VLBW young adults without cerebral palsy compared with 31 term-born controls, at mean age 22.6 ± 0.7 years. The participants were examined with tests of fine and gross motor function (Trail Making Test-5: TMT-5, Grooved Pegboard, Triangle from Movement Assessment Battery for Children-2: MABC-2 and High-level Mobility Assessment Tool: HiMAT) and diffusion tensor imaging (DTI). Probabilistic tractography of motor pathways of the corticospinal tract (CST) and corpus callosum (CC) was performed. Fractional anisotropy (FA) was calculated in non-crossing (capsula interna in CST, body of CC) and crossing (centrum semiovale) fibre regions along the tracts and examined for group differences. Associations between motor test scores and FA in the CST and CC were investigated with linear regression. Tract-based spatial statistics (TBSS) was used to examine group differences in DTI metrics in all major white matter tracts. The VLBW group had lower scores on all motor tests compared with controls, however, only statistically significant for TMT-5. Based on tractography, FA in the VLBW group was lower in non-crossing fibre regions and higher in crossing fibre regions of the CST compared with controls. Within the VLBW group, poorer fine motor function was associated with higher FA in crossing fibre regions of the CST, and poorer bimanual coordination was additionally associated with lower FA in crossing fibre regions of the CC. Poorer gross motor function was associated with lower FA in crossing fibre regions of the CST and CC. There were no associations between motor function and FA in non-crossing fibre regions of the CST and CC within the VLBW group. In the TBSS analysis, the VLBW group had lower FA and higher mean diffusivity compared with controls in all major white matter tracts. The findings in this study may indicate that the associations between motor function and FA are caused by other tracts crossing the CST and CC, and/or by alterations in the periventricular white matter in the centrum semiovale. Some of the associations were in the opposite direction than hypothesized, thus higher FA does not always indicate better function. Furthermore, widespread white matter alterations in VLBW individuals persist into young adulthood. Motor function was associated with FA in crossing fibre regions of CST and CC in VLBW young adults In crossing fibre regions of CST, FA was higher in VLBW than in control young adults TBSS showed lower FA and higher MD in white matter tracts in VLBW than in control young adults
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Key Words
- AD, axial diffusivity
- Brain
- CC, corpus callosum
- CST, corticospinal tract
- DTI, diffusion tensor imaging
- Diffusion tensor imaging
- FA, fractional anisotropy
- HiMAT, high-level mobility assessment tool
- MABC-2, movement assessment battery for children-2
- MD, mean diffusivity
- MNI, Montreal neurological institute
- MRI, magnetic resonance imaging
- Motor function
- NICU, neonatal intensive care unit
- Preterm
- RD, radial diffusivity
- ROI, region-of-interest
- SES, socioeconomic status
- TBSS, tract-based spatial statistics
- TMT-5, Trail Making Test-5
- Tractography
- VLBW, very low birth weight
- VOI, volume-of-interest
- Young adulthood
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High angular resolution diffusion-weighted imaging in mild traumatic brain injury. Neuroimage Clin 2016; 13:174-180. [PMID: 27981032 PMCID: PMC5144744 DOI: 10.1016/j.nicl.2016.11.016] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Revised: 10/24/2016] [Accepted: 11/16/2016] [Indexed: 01/19/2023]
Abstract
We sought to investigate white matter abnormalities in mild traumatic brain injury (mTBI) using diffusion-weighted magnetic resonance imaging (DW-MRI). We applied a global approach based on tract-based spatial statistics skeleton as well as constrained spherical deconvolution tractography. DW-MRI was performed on 102 patients with mTBI within two months post-injury and 30 control subjects. A robust global approach considering only the voxels with a single-fiber configuration was used in addition to global analysis of the tract skeleton and probabilistic whole-brain tractography. In addition, we assessed whether the microstructural parameters correlated with age, time from injury, patient's outcome and white matter MRI hyperintensities. We found that whole-brain global approach restricted to single-fiber voxels showed significantly decreased fractional anisotropy (FA) (p = 0.002) and increased radial diffusivity (p = 0.011) in patients with mTBI compared with controls. The results restricted to single-fiber voxels were more significant and reproducible than those with the complete tract skeleton or the whole-brain tractography. FA correlated with patient outcomes, white matter hyperintensities and age. No correlation was observed between FA and time of scan post-injury. In conclusion, the global approach could be a promising imaging biomarker to detect white matter abnormalities following traumatic brain injury.
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Key Words
- AD, axial diffusivity
- CSD, constrained-spherical deconvolution
- DAI, diffuse axonal injury
- DTI, diffusion tensor imaging
- DW-MRI, diffusion-weighted magnetic resonance imaging
- Diffusion-weighted magnetic resonance imaging
- FA, fractional anisotropy
- GCS, Glasgow Coma Scale
- GOSe, Glasgow Outcome Scale extended
- Global approach
- HARDI, high angular resolution diffusion imaging
- MD, mean diffusivity
- Magnetic resonance imaging
- PTA, post-traumatic amnesia
- Probabilistic tractography
- RD, radial diffusivity
- TBI, traumatic brain injury
- TBSS, tract-based spatial statistics
- Traumatic brain injury
- mTBI, mild traumatic brain injury
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Injury to white matter tracts in relapsing-remitting multiple sclerosis: A possible therapeutic window within the first 5 years from onset using diffusion-tensor imaging tract-based spatial statistics. NEUROIMAGE-CLINICAL 2015; 8:261-6. [PMID: 26106550 PMCID: PMC4474176 DOI: 10.1016/j.nicl.2015.04.020] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/22/2015] [Revised: 04/15/2015] [Accepted: 04/28/2015] [Indexed: 11/23/2022]
Abstract
DTI studies in multiple sclerosis (MS) reveal white matter (WM) injury that occurs with disease progression. In the present study we aimed to elucidate the relationship of microstructural WM damage in patients with varying periods of disease duration. DTI scans were acquired from 90 MS patients and 25 healthy controls. Patients were grouped to short (<1 year), moderate (1 up to 6 years) and long (6–10 years) disease duration periods. Statistical analyses of the fractional anisotropy (FA) data were performed using tract-based spatial statistics (TBSS). Whole-brain skeletal FA measurements showed a significant decrease between healthy controls and the short MS disease duration group, as well as between moderate disease duration and long disease duration groups, but failed to show a significant difference between short and moderate disease duration groups. Voxelwise analysis revealed clusters of diffuse FA reductions in 40 WM tracts when comparing healthy controls and MS short disease duration group, with the point of maximal significant difference located in the left inferior longitudinal fasciculus. Comparing short with long disease duration groups, progressive FA reduction was demonstrated across 30 WM tracts, with the point of maximal significant difference migrating to the body of the corpus callosum. A non-linear pattern of WM microstructure disruption occurs in RRMS. Alterations are seen early in the disease course within 1 year from onset, reach a plateau within the next 5 years, and only later additional WM changes are detected. An important period of a possible therapeutic window therefore exists within the early disease stage. A non-linear pattern of WM microstructure disruption occurs in patients with RRMS. WM disruption is identified within 1 year from disease onset. FA reduction is similar in patients with early and moderate disease duration periods. Different patterns of WM disruption occur in patients with longer disease duration.
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Depressive symptoms and neuroanatomical structures in community-dwelling women: A combined voxel-based morphometry and diffusion tensor imaging study with tract-based spatial statistics. NEUROIMAGE-CLINICAL 2014; 4:481-7. [PMID: 24818074 PMCID: PMC3984445 DOI: 10.1016/j.nicl.2014.03.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/29/2013] [Revised: 03/05/2014] [Accepted: 03/05/2014] [Indexed: 11/29/2022]
Abstract
Depressive symptoms, even at a subclinical level, have been associated with structural brain abnormalities. However, previous studies have used regions of interest or small sample sizes, limiting the ability to generalize the results. In this study, we examined neuroanatomical structures of both gray matter and white matter associated with depressive symptoms across the whole brain in a large sample. A total of 810 community-dwelling adult participants underwent measurement of depressive symptoms with the Center for Epidemiologic Studies Depression Scale (CES-D). The participants were not demented and had no neurological or psychiatric history. To examine the gray and white matter volume, we used structural MRI scans and voxel-based morphometry (VBM); to examine the white matter integrity, we used diffusion tensor imaging with tract-based spatial statistics (TBSS). In female participants, VBM revealed a negative correlation between bilateral anterior cingulate gray matter volume and the CES-D score. TBSS showed a CES-D-related decrease in fractional anisotropy and increase in radial and mean diffusivity in several white matter regions, including the right anterior cingulum. In male participants, there was no significant correlation between gray or white matter volume or white matter integrity and the CES-D score. Our results indicate that the reduction in gray matter volume and differences in white matter integrity in specific brain regions, including the anterior cingulate, are associated with depressive symptoms in women. We studied neuroanatomical structures associated with subclinical depression. The analysis was performed across the whole brain in a large sample. Anterior cingulate gray matter volume reduction was revealed by VBM. Broad white matter integrity differences were revealed by DTI with TBSS. Both changes were seen only in females but not in males.
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Neuroimaging of structural pathology and connectomics in traumatic brain injury: Toward personalized outcome prediction. NEUROIMAGE-CLINICAL 2012; 1:1-17. [PMID: 24179732 PMCID: PMC3757727 DOI: 10.1016/j.nicl.2012.08.002] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/19/2012] [Revised: 08/14/2012] [Accepted: 08/15/2012] [Indexed: 11/01/2022]
Abstract
Recent contributions to the body of knowledge on traumatic brain injury (TBI) favor the view that multimodal neuroimaging using structural and functional magnetic resonance imaging (MRI and fMRI, respectively) as well as diffusion tensor imaging (DTI) has excellent potential to identify novel biomarkers and predictors of TBI outcome. This is particularly the case when such methods are appropriately combined with volumetric/morphometric analysis of brain structures and with the exploration of TBI-related changes in brain network properties at the level of the connectome. In this context, our present review summarizes recent developments on the roles of these two techniques in the search for novel structural neuroimaging biomarkers that have TBI outcome prognostication value. The themes being explored cover notable trends in this area of research, including (1) the role of advanced MRI processing methods in the analysis of structural pathology, (2) the use of brain connectomics and network analysis to identify outcome biomarkers, and (3) the application of multivariate statistics to predict outcome using neuroimaging metrics. The goal of the review is to draw the community's attention to these recent advances on TBI outcome prediction methods and to encourage the development of new methodologies whereby structural neuroimaging can be used to identify biomarkers of TBI outcome.
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Key Words
- 3D, three-dimensional
- AAL, Automatic Anatomical Labeling
- ADC, apparent diffusion coefficient
- ANTS, Advanced Normalization ToolS
- BOLD, blood oxygen level dependent
- CC, corpus callosum
- CT, computed tomography
- DAI, diffuse axonal injury
- DSI, diffusion spectrum imaging
- DTI, diffusion tensor imaging
- DWI, diffusion weighted imaging
- Diffusion tensor
- FA, fractional anisotropy
- FLAIR, Fluid Attenuated Inversion Recovery
- FSE, Functional Status Examination
- GCS, Glasgow Coma Score
- GM, gray matter
- GOS, Glasgow Outcome Score
- GRE, Gradient Recalled Echo
- HARDI, high-angular-resolution diffusion imaging
- IBA, Individual Brain Atlas
- LDA, linear discriminant analysis
- MRI, magnetic resonance imaging
- MRI/fMRI
- NINDS, National Institute of Neurological Disorders and Stroke
- Neuroimaging
- Outcome measures
- PCA, principal component analysis
- PROMO, PROspective MOtion Correction
- SPM, Statistical Parametric Mapping
- SWI, Susceptibility Weighted Imaging
- TBI, traumatic brain injury
- TBSS, tract-based spatial statistics
- Trauma
- WM, white matter
- fMRI, functional magnetic resonance imaging
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