Comparison of Multi-Tensor Diffusion Models' Performance for White Matter Integrity Estimation in Chronic Stroke.
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ABSTRACT:
SUBMITTER: Filatova OG
PROVIDER: S-EPMC5925961 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:OBJECTIVE:To quantify racial differences in brain structural characteristics in white and black octogenarians, and to examine whether these characteristics contribute to cognition. METHODS:Cross-sectional study of 283 adults 79-89 years old (59.4% white;42.0% women) with data on gray matter integrity via diffusion tensor imaging (mean diffusivity), gray matter atrophy (GMA), white matter hyperintensities (WMH), literacy, smoking, drinking, income, hypertension and diabetes. Participants were recruited from an ongoing epidemiological study of older adults living in the community with a range of chronic conditions, physical and cognitive function. Standardized betas (s?) of neuroimaging markers predicting Digit Symbol Substitution Test (DSST) and Modified Mini-Mental State Examination (3MS) scores were computed in multivariable regression models stratified by race. RESULTS:Compared to whites, blacks had lower DSST (p=0.001) and lower 3MS (p=0.006), but also lower mean diffusivity (i.e. higher gray matter microstructural integrity, p=0.032), independent of gender, income, literacy, body mass index, diabetes and drinking habits. Racial differences were not significant for WMH (p=0.062) or GMA (p=0.4). Among blacks, mean diffusivity and WMH were associated with DSST (s?=-.209, p=0.037 and -.211, p=.038, respectively) independent of each other and other covariates; among whites, mean diffusivity, but not WMH, was significantly associated with DSST and 3MS (s? =-.277, p=.002 and -.250, p=0.029, respectively). CONCLUSIONS:In this cohort of octogenarians living in the community, blacks appeared to have higher microstructural integrity of gray matter as compared to whites. This neuroimaging marker was related to higher cognition even in the presence of WMH and other cardiovascular conditions. If confirmed, these findings suggest microstructural gray matter integrity may be a target to improve cognition, especially among blacks who survive to very old age with a range of chronic cardiovascular conditions.
| S-EPMC5127649 | biostudies-literature
Project description:A number of magnetic resonance imaging (MRI) studies have revealed morphological cortical asymmetry in the normal human brain, and reduction or inversion of such hemispheric asymmetry has been reported in schizophrenia. On the other hand, diffusion tensor imaging (DTI) studies have reported inconsistent findings concerning abnormal asymmetry of white matter integrity in schizophrenia. Our aim was to confirm whether there is reduced or inverted asymmetry of white matter integrity in the whole brain in schizophrenia. For this study, 26 right-handed schizophrenia patients, and 32 matched healthy control subjects were investigated. Voxelwise analysis of DTI data was performed using the tract-based spatial statistics. The fractional anisotropy (FA) images were normalized and projected onto the symmetrical white matter skeleton, and the laterality index (LI) of FA, determined by 2 × (left - right)/(left + right), was calculated. The results reveal that schizophrenia patients and healthy controls showed similar patterns of overall FA asymmetries. In the group comparison, patients showed significant reduction of LI in the external capsule (EC), and posterior limb of the internal capsule (PLIC). The EC cluster revealed increased rightward asymmetry, and the PLIC cluster showed reduced leftward asymmetry. Rightward-shift of FA in the EC cluster correlated with negative symptom severity. Considering that the EC cluster includes the uncinate and inferior occipitofrontal fasciculi, which have connections to the orbitofrontal cortex, abnormal asymmetry of white matter integrity in schizophrenia may play a crucial role in the pathogenesis of schizophrenia, through the altered connectivity to the orbitofrontal cortex.
| S-EPMC6870459 | biostudies-literature
Project description:Frontoparietal white matter supports information transfer between brain areas involved in complex haptic tasks such as somatosensory discrimination. The purpose of this study was to gain an understanding of the relationship between microstructural integrity of frontoparietal network white matter and haptic performance in persons with chronic stroke and to compare frontoparietal network integrity in participants with stroke and age matched control participants. Nineteen individuals with stroke and 16 controls participated. Haptic performance was quantified using the Hand Active Sensation Test (HASTe), an 18-item match-to-sample test of weight and texture discrimination. Three tesla MRI was used to obtain diffusion-weighted and high-resolution anatomical images of the whole brain. Probabilistic tractography was used to define 10 frontoparietal tracts total; Four intrahemispheric tracts measured bilaterally 1) thalamus to primary somatosensory cortex (T-S1), 2) thalamus to primary motor cortex (T-M1), 3) primary to secondary somatosensory cortex (S1 to SII) and 4) primary somatosensory cortex to middle frontal gyrus (S1 to MFG) and, 2 interhemispheric tracts; S1-S1 and precuneus interhemispheric. A control tract outside the network, the cuneus interhemispheric tract, was also examined. The diffusion metrics fractional anisotropy (FA), mean diffusivity (MD), axial (AD) and radial diffusivity (RD) were quantified for each tract. Diminished FA and elevated MD values are associated with poorer white matter integrity in chronic stroke. Nine of 10 tracts quantified in the frontoparietal network had diminished structural integrity poststroke compared to the controls. The precuneus interhemispheric tract was not significantly different between groups. Principle component analysis across all frontoparietal white matter tract MD values indicated a single factor explained 47% and 57% of the variance in tract mean diffusivity in stroke and control groups respectively. Age strongly correlated with the shared variance across tracts in the control, but not in the poststroke participants. A moderate to good relationship was found between ipsilesional T-M1 MD and affected hand HASTe score (r = - 0.62, p = 0.006) and less affected hand HASTe score (r = - 0.53, p = 0.022). Regression analysis revealed approximately 90% of the variance in affected hand HASTe score was predicted by the white matter integrity in the frontoparietal network (as indexed by MD) in poststroke participants while 87% of the variance in HASTe score was predicted in control participants. This study demonstrates the importance of frontoparietal white matter in mediating haptic performance and specifically identifies that T-M1 and precuneus interhemispheric tracts may be appropriate targets for piloting rehabilitation interventions, such as noninvasive brain stimulation, when the goal is to improve poststroke haptic performance.
| S-EPMC4683424 | biostudies-literature
Project description:Background Changes in white matter microstructural integrity are detectable before appearance of white matter lesions on magnetic resonance imaging as a manifestation of cerebral small-vessel disease. The information relating poor white matter microstructural integrity to aortic stiffness, a hallmark of aging, is limited. We aimed to examine the association between aortic stiffness and white matter microstructural integrity among older adults. Methods and Results We conducted a cross-sectional study to examine the association between aortic stiffness and white matter microstructural integrity among 1484 men and women (mean age, 76 years) at the 2011 to 2013 examination of the ARIC-NCS (Atherosclerosis Risk in Communities Neurocognitive Study). Aortic stiffness was measured as carotid-femoral pulse wave velocity. Cerebral white matter microstructural integrity was measured as fractional anisotropy and mean diffusivity using diffusion tensor imaging. Multivariable linear regression was used to examine the associations of carotid-femoral pulse wave velocity with fractional anisotropy and mean diffusivity of the overall cerebrum and at regions of interest. Each 1-m/s higher carotid-femoral pulse wave velocity was associated with lower overall fractional anisotropy (β=-0.03; 95% CI, -0.05 to -0.02) and higher overall mean diffusivity (β=0.03; 95% CI, 0.02-0.04). High carotid-femoral pulse wave velocity (upper 25th percentile) was associated with lower fractional anisotropy (β=-0.40; 95% CI, -0.61 to -0.20) and higher overall mean diffusivity (β=0.27; 95% CI, 0.10-0.43). Similar associations were observed at individual regions of interest. Conclusions High aortic stiffness is associated with low cerebral white matter microstructural integrity among older adults. Aortic stiffness may serve as a target for the prevention of poor cerebral white matter microstructural integrity.
| S-EPMC7335527 | biostudies-literature
Project description:BackgroundThis study investigated the efficacy and neurotoxicity of highly active antiretroviral therapy (HAART) by evaluating white matter (WM) injury using diffusion tensor magnetic resonance imaging (DTI) in patients with human immunodeficiency virus (HIV)-associated neurocognitive disorders (HAND).MethodsForty-six patients with HAND underwent DTI before and every six months during HAART treatment. DTI data, including fractional anisotropy (FA) and mean diffusivity (MD) values of structural WM before and after HAART, were compared. The relationship between DTI values and plasma viral loads was tested. MD was more sensitive than FA for evaluating WM injury in HAND-positive patients.ResultsFollowing 12 months of HAART, increased MD values (compared to 6 months of HAART) were observed in the right temporal lobe, right parietal lobe, right occipital lobe, right anterior limb of the internal capsule, right lenticular nucleus, the right cerebral peduncle, left caudate nucleus, left dorsal thalamus, and left posterior limb of the internal capsule. MD values in the left genu of the internal capsule (r=0.350, P=0.017) and left corona radiata (r=0.338, P=0.021) were positively correlated with plasma viral loads.ConclusionsDTI may be useful for assessing the efficacy and neurotoxicity of HAART in HAND-positive patients. Starting HAART may halt WM injury; however, prolonged HAART could worsen WM injury, highlighting the importance of optimal HAART duration.
| S-EPMC7661883 | biostudies-literature
Project description:BackgroundThe progression of FLAIR white matter hyperintensities (WMHs) on MRI heralds vascular-mediated cognitive decline. Even before FLAIR WMH progression, adjacent normal appearing white matter (NAWM) already demonstrates microstructural deterioration on diffusion tensor imaging (DTI). We hypothesized that elevated DTI free water (FW) would precede FLAIR WMH progression, implicating interstitial fluid accumulation as a key pathological step in the progression of cerebral small vessel disease.MethodsParticipants at least 3 months after an ischemic stroke or TIA with WMH on MRI underwent serial brain MRIs every 3 months over the subsequent year. For each participant, the WMHs were automatically segmented, serial MRIs were aligned, and a region of WMH penumbra tissue at risk was defined by dilating lesions at any time point and subtracting baseline lesions. Penumbra voxels were classified as either stable or progressing to WMH if they were segmented as new lesions and demonstrated increasing FLAIR intensity over time. Aligned DTI images included FW and FW-corrected fractional anisotropy (FATissue) and mean diffusivity (MDTissue). Logistic regression and area under the receiver-operator characteristic curve (AUC) were used to test whether baseline DTI predicted voxel-wise classification of stable penumbra or progression to WMH while covarying for clinical risk factors.ResultsIn the included participants (n = 26, mean age 71 ± 9 years, 31% female), we detected a median annual voxel-wise WMH growth of 2.9 ± 2.6 ml. Each baseline DTI metric was associated with lesion progression in the penumbra, but FW had the greatest AUC of 0.732 (0.730 - 0.733) for predicting voxel-wise WMH progression pooled across participants.DiscussionBaseline increased interstitial fluid, estimated as FW on DTI, predicted the progression of NAWM to WMH over the following year. These results implicate the presence of FW in the pathogenesis of cerebral small vessel disease progression.
| S-EPMC10559725 | biostudies-literature
Project description:Stroke is a devastating neurological disease with limited functional recovery. Stroke affects all cellular elements of the brain and impacts areas traditionally classified as both gray matter and white matter. In fact, stroke in subcortical white matter regions of the brain accounts for approximately 30% of all stroke subtypes, and white matter injury is a component of most classes of stroke damage. However, most basic scientific information in stroke cell death and neural repair relates principally to neuronal cell death and repair. Despite an emerging biological understanding of white matter development, adult function, and reorganization in inflammatory diseases, such as multiple sclerosis, little is known of the specific molecular and cellular events in white matter ischemia. This limitation stems in part from the difficulty in generating animal models of white matter stroke. This review will discuss recent progress in studies of animal models of white matter stroke, and the emerging principles of cell death and repair in oligodendrocytes, axons, and astrocytes in white matter ischemic injury.
| S-EPMC3337019 | biostudies-literature
Project description:ObjectiveWe explored the regional pattern of white matter alteration in subjects with metabolic syndrome. We also investigated whether white matter alteration was correlated with BMI.Research design and methodsSeven middle-aged men with metabolic syndrome and seven without metabolic syndrome underwent diffusion tensor imaging with a 3T magnetic resonance imaging imager. We analyzed the fractional anisotropy (FA) values by using a tract-based spatial statistics technique (whole-brain analysis). We subsequently focused on measuring the mean FA values of the right inferior fronto-occipital fasciculus (IFOF) of all subjects by tract-specific analysis (regional brain analysis). We used a Pearson correlation coefficient to evaluate the relationship between BMI and mean FA values of the right IFOF.ResultsIn the whole-brain analysis, subjects with metabolic syndrome had significantly lower FA values than control subjects in part of the right external capsule (part of the right IFOF), the entire corpus callosum, and part of the deep white matter of the right frontal lobe. In the regional brain analysis, the mean FA value of the right IFOF was 0.41 ± 0.03 for subjects with metabolic syndrome and 0.44 ± 0.05 for control subjects. A significant negative correlation was observed between BMI and FA values in the right IFOF (r = -0.56, P < 0.04).ConclusionsOur results show that microstructural white matter changes occur in patients with metabolic syndrome. FA values may be useful indices of white matter alterations in patients with metabolic syndrome.
| S-EPMC3579365 | biostudies-literature
Project description:ObjectiveThe objective of the study was to explore patterns of white matter (WM) alteration in preclinical stage familial Creutzfeldt-Jakob disease (fCJD) using diffusion tensor imaging (DTI).MethodsSeven asymptomatic carriers of the PRNP G114V mutation and six non-carriers were recruited from the same fCJD kindred and follow-up obtained from all asymptomatic carriers and two non-carriers 2 years later. Overlapping WM patterns were also explored in asymptomatic carriers and symptomatic CJD patients. All participants underwent clinical and neuropsychological assessments and DTI at baseline and follow-up. DTI data were subjected to whole-brain voxel-wise analysis of fractional anisotropy (FA) and mean diffusivity (MD) in WM using tract-based spatial statistics. Three comparisons were conducted: baseline carriers against non-carriers (baseline analysis), changes after 2 years in carriers (follow-up analysis), and differences between patients with symptomatic CJD and healthy controls (CJD patient analysis).ResultsNeither carriers nor non-carriers developed any neurological symptoms during 2 years of follow-up. Baseline analysis showed no differences between the carrier and non-carrier groups in MD and FA. Follow-up analysis showed significantly increased MD in multiple WM tracts, among which increased MD in the bilateral superior longitudinal fasciculus, bilateral anterior thalamic radiation, bilateral cingulate gyrus, and left uncinate fasciculus overlapped the patterns observed in patients with symptomatic CJD.ConclusionChanges in integrity within multiple WM tracts can be detected during the preclinical stage of fCJD.
| S-EPMC8171061 | biostudies-literature
Project description:This study set out to determine whether there is white matter involvement in essential tremor (ET), the most common movement disorder. We collected diffusion MRI and analysed differences in fractional anisotropy (FA) and mean diffusivity (MD) between ET patients and control subjects as markers of white matter integrity. We used both classical ROI-based statistics and whole-brain analysis techniques, including voxel-wise analysis with SPM5 and tract-based spatial statistics (TBSS). Using region of interest (ROI) analysis, we found increased MD bilaterally in the inferior cerebellar peduncles (ICP) and reduced FA in the right-sided ICP of ET patients. Whole-brain analyses with TBSS detected increased MD distributed in both motor and nonmotor white matter fibers of ET patients predominantly in the left parietal white matter, while there were no significant FA differences in these areas between ET patients and controls. Voxel-wise analysis with SPM detected significant increase of MD congruent with the highest probability of difference as detected by TBSS. VBM analysis of T1 images did not detect significant differences in either gray or white matter density between our study groups. In summary, we found evidence for changes in white matter MRI properties in ET. The circumscript pathology of the ICP corroborates the pathogenetic concept of the cerebellum and its projections as key structures for tremor generation in ET. Moreover, increased diffusivity in white matter structures of both hemispheres suggests widespread alterations of fiber integrity in motor and nonmotor networks in ET patients. The underlying cause of the DTI changes observed remains to be elucidated.
| S-EPMC6870356 | biostudies-literature