Perivascular space fluid contributes to diffusion tensor imaging changes in white matter.
Ontology highlight
ABSTRACT:
SUBMITTER: Sepehrband F
PROVIDER: S-EPMC6591070 | biostudies-literature | 2019 Aug
REPOSITORIES: biostudies-literature
Publications
Perivascular space fluid contributes to diffusion tensor imaging changes in white matter.
Sepehrband Farshid F Cabeen Ryan P RP Choupan Jeiran J Barisano Giuseppe G Law Meng M Toga Arthur W AW
NeuroImage 20190430
Diffusion tensor imaging (DTI) has been extensively used to map changes in brain tissue related to neurological disorders. Among the most widespread DTI findings are increased mean diffusivity and decreased fractional anisotropy of white matter tissue in neurodegenerative diseases. Here we utilize multi-shell diffusion imaging to separate diffusion signal of the brain parenchyma from non-parenchymal fluid within the white matter. We show that unincorporated anisotropic water in perivascular spac ...[more]
Similar Datasets
Project description:Background: Early pathological changes in white matter microstructure can be studied using the diffusion tensor imaging (DTI). It is not only important to study these subtle pathological changes leading to cognitive decline, but also to ascertain how an intervention would impact the white matter microstructure and cognition in persons at-risk of dementia.Objectives: To study the impact of a multidomain lifestyle intervention on white matter and cognitive changes during the 2-year Finnish Geriatric Intervention Study to prevent Cognitive Impairment and Disability (FINGER), a randomized controlled trial in at-risk older individuals (age 60-77 years) from the general population.Methods: This exploratory study consisted of a subsample of 60 FINGER participants. Participants were randomized to either a multidomain intervention (diet, exercise, cognitive training, and vascular risk management, n?=?34) or control group (general health advice, n?=?26). All underwent baseline and 2-year brain DTI. Changes in fractional anisotropy (FA), diffusivity along domain (F1) and non-domain (F2) diffusion orientations, mean diffusivity (MD), axial diffusivity (AxD), radial diffusivity (RD), and their correlations with cognitive changes during the 2-year multidomain intervention were analyzed.Results: FA decreased, and cognition improved more in the intervention group compared to the control group (p?<?0.05), with no significant intergroup differences for changes in F1, F2, MD, AxD, or RD. The cognitive changes were significantly positively related to FA change, and negatively related to RD change in the control group, but not in the intervention group.Conclusion: The 2-year multidomain FINGER intervention may modulate white matter microstructural alterations.
| S-EPMC7683078 | biostudies-literature
Project description:BACKGROUND:White matter alterations have been observed in patients with migraine. However, no microstructural white matter alterations have been found particularly in episodic or chronic migraine patients, and there is limited research focused on the comparison between these two groups of migraine patients. METHODS:Fifty-one healthy controls, 55 episodic migraine patients and 57 chronic migraine patients were recruited and underwent brain T1-weighted and diffusion-weighted MRI acquisition. Using Tract-Based Spatial Statistics (TBSS), fractional anisotropy, mean diffusivity, radial diffusivity and axial diffusivity were compared between the different groups. On the one hand, all migraine patients were compared against healthy controls. On the other hand, patients from each migraine group were compared between them and also against healthy controls. Correlation analysis between clinical features (duration of migraine in years, time from onset of chronic migraine in months, where applicable, and headache and migraine frequency, where applicable) and Diffusion Tensor Imaging measures was performed. RESULTS:Fifty healthy controls, 54 episodic migraine and 56 chronic migraine patients were finally included in the analysis. Significant decreased axial diffusivity (p?<?.05 false discovery rate and by number of contrasts corrected) was found in chronic migraine compared to episodic migraine in 38 white matter regions from the Johns Hopkins University ICBM-DTI-81 White-Matter Atlas. Significant positive correlation was found between time from onset of chronic migraine and mean fractional anisotropy in the bilateral external capsule, and negative correlation between time from onset of chronic migraine and mean radial diffusivity in the bilateral external capsule. CONCLUSIONS:These findings suggest global white matter structural differences between episodic migraine and chronic migraine. Patients with chronic migraine could present axonal integrity impairment in the first months of chronic migraine with respect to episodic migraine patients. White matter changes after the onset of chronic migraine might reflect a set of maladaptive plastic changes.
| S-EPMC6941267 | biostudies-literature
Project description:Background and purposeLoss of integrity in nonlesional white matter occurs as a fundamental feature of multiple sclerosis in adults. The purpose of our study was to evaluate DTI-derived measures of white matter microstructure in children with MS compared with age- and sex-matched controls by using tract-based spatial statistics.Materials and methodsFourteen consecutive pediatric patients with MS (11 female/3 male; mean age, 15.1 ± 1.6 years; age range, 12-17 years) and age- and sex-matched healthy subjects (11 female/3 male; mean age, 14.8 ± 1.7 years) were included in the study. After we obtained DTI sequences, data processing was performed by using tract-based spatial statistics.ResultsCompared with healthy age- and sex-matched controls, children with multiple sclerosis showed a global decrease in mean fractional anisotropy (P ≤ .001), with a concomitant increase in mean (P < .001), radial (P < .05), and axial diffusivity (P < .001). The most pronounced fractional anisotropy value decrease in patients with MS was found in the splenium of the corpus callosum (P < .001). An additional decrease in fractional anisotropy was identified in the right temporal and right and left parietal regions (P < .001). Fractional anisotropy of the white matter skeleton was related to disease duration and may, therefore, serve as a diagnostic marker.ConclusionsThe microstructure of white matter is altered early in the disease course in childhood multiple sclerosis.
| S-EPMC7965410 | 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
Project description:Background and purposeCurrent approaches to diffusion tensor imaging (DTI) analysis do not permit identification of individual-level changes in DTI indices. We investigated the ability of wild bootstrapping analysis to detect subject-specific changes in brain white matter (WM) before and after sports-related concussion.Materials and methodsA prospective cohort study was performed in nine high school athletes engaged in hockey or football and six controls. Subjects underwent DTI pre- and postseason within a 3-month interval. One athlete was diagnosed with concussion (scanned within 72 h), and eight suffered between 26 and 399 subconcussive head blows. Fractional anisotropy (FA) and mean diffusivity (MD) were measured in each WM voxel. Bootstrap samples were generated, and a permuted t test was used to compare voxel-wise FA/MD changes in each subject pre- vs. postseason.ResultsThe percentage of WM voxels with significant (p<.05) pre-post FA changes was highest for the concussion subject (3.2%), intermediary for those with subconcussive head blows (mean 1.05%±.15%) and lowest for controls (mean 0.28%±.01%). Similarly, the percentage of WM voxels with significant MD changes was highest for the concussion subject (3.44%), intermediary for those with subconcussive head blows (mean 1.48%±.17%) and lowest for controls (mean 0.48%±.05%). Significantly changed FA and MD voxels colocalized in the concussion subject to the right corona radiata and right inferior longitudinal fasciculus.ConclusionsWild bootstrap analysis detected significantly changed WM in a single concussed athlete. Athletes with multiple subconcussive head blows had significant changes in a percentage of their WM that was over three times higher than controls. Efforts to understand the significance of these WM changes and their relationship to head impact forces appear warranted.
| S-EPMC3254806 | biostudies-literature
Project description:OBJECTIVES:Idiopathic-generalized epilepsy (IGE) is currently considered to be a genetic disease without structural alterations on conventional MRI. However, voxel-based morphometry has shown abnormalities in IGE. Another method to analyze the microstructure of the brain is diffusion-tensor imaging (DTI). We sought to clarify which structural alterations are present in IGE and the most frequent subsyndrome juvenile myoclonic epilepsy (JME). EXPERIMENTAL DESIGN:We studied 25 patients (13 IGE and 12 JME) and 44 healthy controls with DTI. Fractional anisotropy (FA), mean diffusivity (MD), axial and radial diffusivity (AD/RD) were calculated and group differences were analyzed using tract-based spatial statistics (TBSS). Additionally we performed a target-based classification of TBSS results based on the Freesurfer cortical regions. PRINCIPLE OBSERVATIONS: TBSS showed widespread FA reductions as well as MD and RD increases in patients compared to controls. Affected areas were corpus callosum, corticospinal tract, superior and inferior longitudinal fasciculus and supplementary motor regions. No significant differences were found between JME and IGE subgroups. The target-based classification confirmed a particular involvement of the superior frontal gyrus (mesiofrontal area) in IGE/ME. CONCLUSIONS:IGE and JME patients showed clear microstructural alterations in several large white matter tracts. Similar findings have been reported in rodent models of IGE. Previous, region-of-interest-based DTI studies may have under-estimated the spatial extent of structural loss associated with generalized epilepsy. The comparison of clinically defined JME and IGE groups revealed no significant DTI differences in our cohort.
| S-EPMC6869818 | biostudies-literature
Project description:Alcoholism-related deficits in cognition and emotion point toward frontal and limbic dysfunction, particularly in the right hemisphere. Prefrontal and anterior cingulate cortices are involved in cognitive and emotional functions and play critical roles in the oversight of the limbic reward system. In the present study, we examined the integrity of white matter tracts that are critical to frontal and limbic connectivity.Diffusion tensor magnetic resonance imaging (DT-MRI) was used to assess functional anisotropy (FA), a measure of white matter integrity, in 15 abstinent long-term chronic alcoholic and 15 demographically equivalent control men. Voxel-based and region-based analyses of group FA differences were applied to these scans.Alcoholic subjects had diminished frontal lobe FA in the right superior longitudinal fascicles II and III, orbitofrontal cortex white matter, and cingulum bundle, but not in corresponding left hemisphere regions. These right frontal and cingulum white matter regional FA measures provided 97% correct group discrimination. Working Memory scores positively correlated with superior longitudinal fascicle III FA measures in control subjects only.The findings demonstrate white matter microstructure deficits in abstinent alcoholic men in several right hemisphere tracts connecting prefrontal and limbic systems. These white matter deficits may contribute to underlying dysfunction in memory, emotion, and reward response in alcoholism.
| S-EPMC4105344 | biostudies-literature
Project description:Multiple functional methods including functional magnetic resonance imaging, transcranial magnetic stimulation, and positron emission tomography have shown cortical reorganization in response to blindness. We investigated microanatomical correlates of this reorganization using diffusion tensor imaging and diffusion tensor tractography (DTT). Five early blind (EB) were compared with 7 normally sighted (NS) persons. DTT showed marked geniculocalcarine tract differences between EB and NS participants. All EB participants showed evidence of atrophy of the geniculocortical tracts. Connections between visual cortex and the orbital frontal and temporal cortices were relatively preserved in the EB group. Importantly, no additional tracts were found in any EB participant. Significant alterations of average diffusivity and relative anisotropy were found in the white matter (WM) of the occipital lobe in the EB group. These observations suggest that blindness leads to a reorganization of cerebral WM and plausibly support the hypothesis that visual cortex functionality in blindness is primarily mediated by corticocortical as opposed to thalamocortical connections.
| S-EPMC3789517 | biostudies-literature
Project description:Tuberculous meningitis (TBM) and cryptococcal meningitis (CM) are two of the most common types of chronic meningitis. This study aimed to assess whether chronic neuro-psychological sequelae are associated with micro-structure white matter (WM) damage in HIV-negative chronic meningitis. Nineteen HIV-negative TBM patients, 13 HIV-negative CM patients, and 32 sex- and age-matched healthy volunteers were evaluated and compared. The clinical relevance of WM integrity was studied using voxel-based diffusion tensor imaging (DTI) magnetic resonance imaging. All of the participants underwent complete medical and neurologic examinations, and neuro-psychological testing. Differences in DTI indices correlated with the presence of neuro-psychological rating scores and cerebrospinal fluid (CSF) analysis during the initial hospitalization. Patients with CM had more severe cognitive deficits than healthy subjects, especially in TBM. There were changes in WM integrity in several limbic regions, including the para-hippocampal gyrus and cingulate gyrus, and in the WM close to the globus pallidus. A decline in WM integrity close to the globus pallidus and anterior cingulate gyrus was associated with worse CSF analysis profiles. Poorer DTI parameters directly correlated with worse cognitive performance on follow-up. These correlations suggest that WM alterations may be involved in the psychopathology and pathophysiology of co-morbidities. Abnormalities in the limbic system and globus pallidus, with their close relationship to the CSF space, may be specific biomarkers for disease evaluation.
| S-EPMC4043527 | biostudies-literature
Project description:A growing body of research indicates benefits of cognitive training in older adults, but the neuronal mechanisms underlying the effect of cognitive intervention remains largely unexplored. Neuroimaging methods are sensitive to subtle changes in brain structure and show potential for enhancing our understanding of both aging- and training-related neuronal plasticity. Specifically, studies using diffusion tensor imaging (DTI) suggest substantial changes in white matter (WM) in aging, but it is not known whether cognitive training might modulate these structural alterations. We used tract-based spatial statistics (TBSS) optimized for longitudinal analysis to delineate the effects of 8 weeks intensive memory training on WM microstructure. 41 participants (mean age 61 years) matched for age, sex and education were randomly assigned to an intervention or control group. All participants underwent MRI-scanning and neuropsychological assessments at the beginning and end of the study. Longitudinal analysis across groups revealed significant increase in frontal mean diffusivity (MD), indicating that DTI is sensitive to WM structural alterations over a 10-week interval. Further, group analysis demonstrated positive effects of training on the short-term changes. Participants in the training group showed a relative increase in fractional anisotropy (FA) compared with controls. Further, a significant relationship between memory improvement and change in FA was found, suggesting a possible functional significance of the reported changes. The training effect on FA seemed to be driven by a relative decrease in radial diffusivity, which might indicate a role for myelin-related processes in WM plasticity.
| S-EPMC6870063 | biostudies-literature