scholarly journals Pervasive White Matter Fiber Degeneration in Ischemic Stroke

Stroke ◽  
2020 ◽  
Vol 51 (5) ◽  
pp. 1507-1513 ◽  
Author(s):  
Natalia Egorova ◽  
Thijs Dhollander ◽  
Mohamed Salah Khlif ◽  
Wasim Khan ◽  
Emilio Werden ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
White Matter ◽  
Cross Section ◽  
Corticospinal Tract ◽  
Brain Volume ◽  
Morphological Changes ◽  
Axonal Loss ◽  
Fiber Density ◽  
Whole Brain ◽  
Brain Volume Loss

Background and Purpose— We examined if ischemic stroke is associated with white matter degeneration predominantly confined to the ipsi-lesional tracts or with widespread bilateral axonal loss independent of lesion laterality. Methods— We applied a novel fixel-based analysis, sensitive to fiber tract–specific differences within a voxel, to assess axonal loss in stroke (N=104, 32 women) compared to control participants (N=40, 15 women) across the whole brain. We studied microstructural differences in fiber density and macrostructural (morphological) changes in fiber cross-section. Results— In participants with stroke, we observed significantly lower fiber density and cross-section in areas adjacent, or connected, to the lesions (eg, ipsi-lesional corticospinal tract). In addition, the changes extended beyond directly connected tracts, independent of the lesion laterality (eg, corpus callosum, bilateral inferior fronto-occipital fasciculus, right superior longitudinal fasciculus). Conclusions— We conclude that ischemic stroke is associated with extensive neurodegeneration that significantly affects white matter integrity across the whole brain. These findings expand our understanding of the mechanisms of brain volume loss and delayed cognitive decline in stroke.

scholarly journals Fiber-specific white matter alterations in early-stage tremor-dominant Parkinson’s disease

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Christina Andica ◽  
Koji Kamagata ◽  
Yuya Saito ◽  
Wataru Uchida ◽  
Shohei Fujita ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
White Matter ◽  
Cross Section ◽  
Corticospinal Tract ◽  
Early Stage ◽  
Brain Regions ◽  
Fiber Density ◽  
Compensation Mechanisms ◽  
Progression Markers

AbstractUsing a fixel-based analysis (FBA), we assessed the fiber-specific white matter (WM) alterations in nonmedicated patients with early-stage Parkinson’s disease (PD) with tremor-dominant (TD; n = 53; mean age, 61.7 ± 8.7 years) and postural instability and gait disorder (PIGD; n = 27; mean age, 57.8 ± 8.1 years) motor subtypes and age- and sex-matched healthy controls (HC; n = 43; mean age, 61.6 ± 9.2 years) from Parkinson’s Progression Markers Initiative dataset. FBA revealed significantly increased macrostructural fiber cross section and a combination of fiber density and cross section metrics within the corticospinal tract in patients with TD-PD compared with HC. Nonetheless, no significant changes in FBA-derived metrics were found in patients with PIGD-PD compared with HC or patients with TD-PD. Our results may provide evidence of WM neural compensation mechanisms in patients with TD-PD marked by increases in fiber bundle size and the ability to relay information between brain regions.

Childhood multiple sclerosis is associated with reduced brain volumes at first clinical presentation and brain growth failure

2019 ◽  
Vol 25 (7) ◽  
pp. 927-936 ◽  
Author(s):  
Frederik Bartels ◽  
Katharina Nobis ◽  
Graham Cooper ◽  
Eva Wendel ◽  
Robert Cleaveland ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
White Matter ◽  
Clinical Presentation ◽  
Brain Volume ◽  
Volume Loss ◽  
Brain Growth ◽  
Whole Brain ◽  
Brain Volumes ◽  
Brain Volume Loss

Background: Paediatric multiple sclerosis (pedMS) patients at a single site were shown to have reduced brain volumes and failure of age-expected brain growth compared to healthy controls. However, the precise time of onset of brain volume loss remains unclear. Objective: To longitudinally study brain volumes in a multi-centre European cohort at first presentation and after 2 years. Methods: Brain volumes of high-resolution magnetic resonance imaging (MRI) data from 37 pedMS patients at first presentation prior to steroid therapy and at 2-year follow-up ( n = 21) were compared to matched longitudinal MRI data from the NIH Paediatric MRI Data Repository. Results: Patients showed significantly reduced whole brain, grey and white matter and increased ventricular volumes at initial presentation and at follow-up compared to controls. Over 2 years, patients exhibited significant reduction of whole brain and white matter volumes, accompanied by increased ventricular volume. Brain volume loss at follow-up correlated with a higher number of infratentorial lesions, relapses and an increased Expanded Disability Status Scale (EDSS) score. Conclusions: In pedMS patients, brain volume loss is present already at first clinical presentation and accelerated over 2 years. Increased disease activity is associated with more severe brain volume loss. MRI brain volume change might serve as an outcome parameter in future prospective pedMS studies.

Hippocampal atrophy, whole brain volume, and white matter lesions in older hypertensive subjects

Neurology ◽  
2004 ◽  
Vol 63 (10) ◽  
pp. 1892-1897 ◽  
Author(s):  
R. M. Wiseman ◽  
B. K. Saxby ◽  
E. J. Burton ◽  
R. Barber ◽  
G. A. Ford ◽  
...  
Keyword(s):  
White Matter ◽  
Brain Volume ◽  
White Matter Lesions ◽  
Hippocampal Atrophy ◽  
Whole Brain

P.1.e.028 Increase of whole brain volume and gray and white matter tissue in OCD: a volumetric and voxel-based morphometry MRI study

2010 ◽  
Vol 20 ◽  
pp. S303-S304
Author(s):  
T. Sobanski ◽  
G. Wagner ◽  
G. Peikert ◽  
U. Gruhn ◽  
H. Sauer ◽  
...  
Keyword(s):  
White Matter ◽  
Brain Volume ◽  
Voxel Based Morphometry ◽  
Whole Brain ◽  
Mri Study

Brain volume reductions in medication-naive patients with schizophrenia in relation to intelligence quotient

2012 ◽  
Vol 42 (9) ◽  
pp. 1847-1856 ◽  
Author(s):  
M. Rais ◽  
W. Cahn ◽  
H. G. Schnack ◽  
H. E. Hulshoff Pol ◽  
R. S. Kahn ◽  
...  
Keyword(s):  
White Matter ◽  
Healthy Subjects ◽  
Intelligence Quotient ◽  
Brain Volume ◽  
First Episode ◽  
Volume Loss ◽  
White Matter Volume ◽  
Matter Volume ◽  
Brain Volume Loss ◽  
First Episode Schizophrenia

BackgroundGlobal brain abnormalities such as brain volume loss and grey- and white-matter deficits are consistently reported in first-episode schizophrenia patients and may already be detectable in the very early stages of the illness. Whether these changes are dependent on medication use or related to intelligence quotient (IQ) is still debated.MethodMagnetic resonance imaging scans were obtained for 20 medication-naive patients with first-episode schizophrenia and 26 matched healthy subjects. Volume measures of total brain grey and white matter, third and lateral ventricles and cortical thickness/surface were obtained. Differences between the groups were investigated, taking into account the effect of intelligence.ResultsMedication-naive patients showed statistically significant reductions in whole-brain volume and cerebral grey- and white-matter volume together with lateral ventricle enlargement compared to healthy subjects. IQ was significantly lower in patients compared to controls and was positively associated with brain and white-matter volume in the whole group. No significant differences in cortical thickness were found between the groups but medication-naive patients had a significantly smaller surface in the left superior temporal pole, Heschl's gyrus and insula compared to controls.ConclusionsOur findings suggest that brain volume loss is present at illness onset, and can be explained by the reduced surface of the temporal and insular cortex. These abnormalities are not related to medication, but IQ.

scholarly journals Comparative Study of Multi-Delay Pseudo-Continuous Arterial Spin Labeling Perfusion MRI and CT Perfusion in Ischemic Stroke Disease

2021 ◽  
Vol 15 ◽  
Author(s):  
Xi Xu ◽  
Zefeng Tan ◽  
Meng Fan ◽  
Mengjie Ma ◽  
Weimin Fang ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
White Matter ◽  
Gray Matter ◽  
Arterial Spin Labeling ◽  
Ct Perfusion ◽  
Pearson Correlation ◽  
Correlation Coefficients ◽  
Spin Labeling ◽  
Whole Brain ◽  
Continuous Arterial Spin Labeling

With the aging population, stroke has gradually become the leading cause of death and disability among adults. It is necessary to verify whether multi-delay pseudo-continuous arterial spin labeling (pCASL) MRI can be used as a standard neuroimaging protocol in the patients with ischemic stroke. We aimed to investigate the clinical utility of multi-delay pCASL for evaluating cerebral perfusion in ischemic stroke disease. Twenty-one ischemic stroke patients [18 men and 3 women; median age, 62 years (age range, 37–84 years)] were enrolled in this study. All patients underwent examinations, including the multi-delay pCASL protocol (using 6 PLDs between 1,000 and 3,500 ms) and computed tomography perfusion (CTP). The cerebral blood flow (CBF) and arterial transit time (ATT) maps were obtained by the multi-delay pCASL protocol, while CBF and mean transit time (MTT) maps were derived by CTP measurements. Based on the voxel level analysis, Pearson correlation coefficients were used to estimate the associations between the two modalities in the gray matter, white matter, and whole brain of each subject. Moderate to high positive associations between ASL-CBF and CTP-CBF were acquired by voxel-level-wise analysis in the gray matter, white matter, and whole brain of the enrolled patients (all P < 0.005), and the average Pearson correlation coefficients were 0.647, 0.585, and 0.646, respectively. Highly significant positive correlations between ASL-ATT and CTP-MTT were obtained by voxel-level-wise associations in the gray matter, white matter, and whole brain (all P < 0.005), and the average Pearson correlation coefficients were 0.787, 0.707, and 0.799, respectively. In addition, significant associations between ASL and CT perfusion were obtained in the gray, white matter and whole brain, according to the subgroup analyses of patient’s age and disease stage. There is a correlation between perfusion parameters from multi-delay pCASL and CT perfusion imaging in patients with ischemic stroke. Multi-delay pCASL is radiation-free and non-invasive, and could be an alternative method to CT scans for assessing perfusion in ischemic stroke disease.

scholarly journals Detecting Corticospinal Tract Impairment in Tumor Patients With Fiber Density and Tensor-Based Metrics

2021 ◽  
Vol 10 ◽  
Author(s):  
Lucius S. Fekonja ◽  
Ziqian Wang ◽  
Dogu B. Aydogan ◽  
Timo Roine ◽  
Melina Engelhardt ◽  
...  
Keyword(s):  
White Matter ◽  
Cross Sections ◽  
Motor System ◽  
Structural Changes ◽  
Corticospinal Tract ◽  
Fiber Density ◽  
Who Grade ◽  
Entire Cohort ◽  
Spherical Deconvolution ◽  
Apparent Diffusion

Tumors infiltrating the motor system lead to significant disability, often caused by corticospinal tract injury. The delineation of the healthy-pathological white matter (WM) interface area, for which diffusion magnetic resonance imaging (dMRI) has shown promising potential, may improve treatment outcome. However, up to 90% of white matter (WM) voxels include multiple fiber populations, which cannot be correctly described with traditional metrics such as fractional anisotropy (FA) or apparent diffusion coefficient (ADC). Here, we used a novel fixel-based along-tract analysis consisting of constrained spherical deconvolution (CSD)-based probabilistic tractography and fixel-based apparent fiber density (FD), capable of identifying fiber orientation specific microstructural metrics. We addressed this novel methodology’s capability to detect corticospinal tract impairment. We measured and compared tractogram-related FD and traditional microstructural metrics bihemispherically in 65 patients with WHO grade III and IV gliomas infiltrating the motor system. The cortical tractogram seeds were based on motor maps derived by transcranial magnetic stimulation. We extracted 100 equally distributed cross-sections along each streamline of corticospinal tract (CST) for along-tract statistical analysis. Cross-sections were then analyzed to detect differences between healthy and pathological hemispheres. All metrics showed significant differences between healthy and pathologic hemispheres over the entire tract and between peritumoral segments. Peritumoral values were lower for FA and FD, but higher for ADC within the entire cohort. FD was more specific to tumor-induced changes in CST than ADC or FA, whereas ADC and FA showed higher sensitivity. The bihemispheric along-tract analysis provides an approach to detect subject-specific structural changes in healthy and pathological WM. In the current clinical dataset, the more complex FD metrics did not outperform FA and ADC in terms of describing corticospinal tract impairment.

scholarly journals NIMG-55. A QUANTITATIVE ANALYSIS OF BRAIN VOLUME DYNAMICS IN PCNSL PATIENTS TREATED WITH HIGH-DOSE METHOTREXATE-BASED THERAPY

2020 ◽  
Vol 22 (Supplement_2) ◽  
pp. ii160-ii160
Author(s):  
Ananyaa Sivakumar ◽  
David Kamson ◽  
Fayez Estephan ◽  
Sebastian Lambrecht ◽  
Omar Dzaye ◽  
...  
Keyword(s):  
White Matter ◽  
Brain Volume ◽  
Primary Cns Lymphoma ◽  
Cns Lymphoma ◽  
High Dose ◽  
High Dose Methotrexate ◽  
Volume Loss ◽  
Brain Volumes ◽  
Brain Volume Loss ◽  
Dose Methotrexate

Abstract BACKGROUND Primary CNS lymphoma (PCNSL) is a rare, infiltrative disease. High-dose methotrexate (HD-MTX) is the backbone of induction regimens for PCNSL. While MTX-associated white matter changes are well-described, treatment-related brain volume loss is much less understood, especially in radiotherapy-naïve cohorts. Here, we aimed to longitudinally quantify the rates of brain volume loss in PCNSL patients treated with HD-MTX. SUBJECTS/METHODS We included 12 radiotherapy-naïve patients (age mean±SD 61±15y, range 37-84y, 9F) with histopathologically confirmed PCNSL who received HD-MTX induction (mean±SD 12±4 cycles, range 8-18) +/-rituximab. MRIs were collected from within 1 month of HD-MTX initiation until the end of follow-up (mean±SD: 3.7±2.9y). Longitudinal whole-brain segmentation was performed on FLAIR images using the Sequence Adaptive Multimodal Segmentation tool of FreeSurfer. Brain volumes were normalized to the initial scan, white matter lesion volumes were normalized to cerebral volume (nWML). RESULTS The average rate of cerebral volume change was -2.1±1.9%/year. Half of patients showed marked cerebral volume loss in the first year (-5.6±1.4% vs. -2.0±1.4%; n=10; p=0.003) with the most prominent change occurring within 6-months of treatment initiation (-4.2±1.7% vs. -0.5±1.6; n=12; p=0.004). Cerebral volume loss reached a plateau after the 1-year mark in both groups (0.3±0.8%/year vs. 1.4±3.3%/year; n=8; p=0.4). Patients younger than 61 years exhibited markedly higher rates of cerebral volume loss (-6.2±1.1%/year vs. 2.4±1.5%/year p=0.003), which was corroborated by strong inverse correlation between age and cerebral volume loss (Pearson’s r=-0.82, p=0.004). Neither the cerebellar volume, nor the nWML load correlated with age. CONCLUSION In the present cohort, brain volume loss was approximately four-fold higher than what is described in the healthy aging. Younger patients treated with HD-MTX exhibited more severe cerebral volume loss, which may be due to higher initial brain volume reserve. Detailed analyses of a larger sample are underway.

Rest–activity functioning is related to white matter microarchitecture and modifiable risk factors in older adults at-risk for dementia

SLEEP ◽  
2021 ◽  
Author(s):  
Jake R Palmer ◽  
Shantel L Duffy ◽  
Susanne Meares ◽  
Jonathon Pye ◽  
Fernando Calamante ◽  
...  
Keyword(s):  
Risk Factors ◽  
Older Adults ◽  
At Risk ◽  
Depressive Symptoms ◽  
White Matter ◽  
Cross Section ◽  
Vascular Risk Factors ◽  
Vascular Risk ◽  
Fiber Density ◽  
Rest Activity

Abstract Study Objectives Growing evidence demonstrates pronounced alterations in rest–activity functioning in older adults at-risk for dementia. White matter degeneration, poor cardiometabolic functioning, and depression have also been linked to a greater risk of decline; however, limited studies have examined the white matter in relation to rest–activity functioning in at-risk older adults. Methods We investigated associations between nonparametric actigraphy measures and white matter microarchitecture using whole-brain fixel-based analysis of diffusion-weighted imaging in older adults (aged 50 years or older) at-risk for cognitive decline and dementia. The fixel-based metrics assessed were fiber density, fiber cross-section, and combined fiber-density, and cross-section. Interactions between rest–activity functioning and known clinical risk factors, specifically body mass index (BMI), vascular risk factors, depressive symptoms and self-reported exercise, and their association with white matter properties were then investigated. Results Sixty-seven older adults were included (mean = 65.78 years, SD = 7.89). Lower relative amplitude, poorer 24-h synchronization and earlier onset of the least active 5-h period were associated with reductions in markers of white matter atrophy in widespread regions, including cortico-subcortical and cortical association pathways. Preliminary evidence was also found indicating more pronounced white matter alterations in those with lower amplitude and higher BMI (β = 0.25, 95% CI [0.05, 0.46]), poorer 24-h synchronization and more vascular risk factors (β = 0.17, 95% CI [–0.02, 0.36]) and earlier onset of inactivity and greater depressive symptoms (β = 0.17, 95% CI [0.03, 0.30]). Conclusions These findings highlight the complex interplay between rest–activity rhythms, white matter, and clinical risk factors in individuals at-risk for dementia that should be considered in future studies.

scholarly journals Structural Connectivity Remote From Lesions Correlates With Somatosensory Outcome Poststroke

Stroke ◽  
2021 ◽  
Author(s):  
Chia-Lin Koh ◽  
Chun-Hung Yeh ◽  
Xiaoyun Liang ◽  
Rishma Vidyasagar ◽  
Rüdiger J. Seitz ◽  
...  
Keyword(s):  
White Matter ◽  
Cross Section ◽  
Fiber Bundle ◽  
Spatial Information ◽  
Structural Connectivity ◽  
Healthy Adults ◽  
Lesion Group ◽  
Fiber Density ◽  
White Matter Tracts ◽  
Stroke Lesion

Background and Purpose: Changes in connectivity of white matter fibers remote to a stroke lesion, suggestive of structural connectional diaschisis, may impact on clinical impairment and recovery after stroke. However, until recently, we have not had tract-specific techniques to map changes in white matter tracts in vivo in humans to enable investigation of potential mechanisms and clinical impact of such remote changes. Our aim was to identify and quantify white matter tracts that are affected remote from a stroke lesion and to investigate the associations between reductions in tract-specific connectivity and impaired touch discrimination function after stroke. Methods: We applied fixel-based analysis to diffusion magnetic resonance imaging data from 37 patients with stroke (right lesion =16; left lesion =21) and 26 age-matched healthy adults. Three quantitative metrics were compared between groups: fiber density; fiber-bundle cross-section; and a combined measure of both (fiber-bundle cross-section) that reflects axonal structural connectivity. Results: Compared with healthy adults, patients with stroke showed significant common fiber-bundle cross-section and fiber density reductions in 4 regions remote from focal lesions that play roles in somatosensory and spatial information processing. Structural connectivity along the somatosensory fibers of the lesioned hemisphere was correlated with contralesional hand touch function. Touch function of the ipsilesional hand was associated with connectivity of the superior longitudinal fasciculus, and, for the right-lesion group, the corpus callosum. Conclusions: Remote tract-specific reductions in axonal connectivity indicated by diffusion imaging measures are observed in the somatosensory network after stroke. These remote white matter connectivity reductions, indicative of structural connectional diaschisis, are associated with touch impairment in patients with stroke.

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