Changes in White Matter Microstructure over 3 Years in People with and Without Stroke

Natalia Egorova-Brumley, Thijs Dhollander, Wasim Khan, Mohamed Salah Khlif, Deena Ebaid, Amy Brodtmann

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Abstract

Background and ObjectivesCerebral white matter health can be estimated by MRI-derived indices of microstructure. White matter dysfunction is increasingly recognized as a contributor to neurodegenerative disorders affecting cognition and to functional outcomes after stroke. Reduced indices of white matter microstructure have been demonstrated cross-sectionally in stroke survivors compared with stroke-free participants, but longitudinal changes in the structure of white matter after stroke remain largely unexplored. We aimed to characterize white matter micro-and macrostructure over 3 years after stroke and study associations with white matter metrics and cognitive functions.MethodsPatients with first-ever or recurrent ischemic stroke of any etiology in any vascular territory were compared with stroke-free age-and sex-matched controls. Those diagnosed with hemorrhagic stroke, TIA, venous infarction, or significant medical comorbidities, psychiatric and neurodegenerative disorders, substance abuse, or history of dementia were excluded. Diffusion-weighted MRI data at 3, 12, and 36 months were analyzed using a longitudinal fixel-based analysis, sensitive to fiber tract-specific differences within a voxel. It was used to examine whole-brain white matter degeneration in stroke compared with control participants. We studied microstructural differences in fiber density and macrostructural changes in fiber-bundle cross-section, in relation to cognitive performance. Analyses were performed controlling for age, intracranial volume, and education (family-wise error-corrected p < 0.05, nonparametric testing over 5,000 permutations).ResultsWe included 71 participants with stroke (age 66 ± 12 years, 22 women) and 36 controls (age 69 ± 5 years, 13 women). We observed extensive white matter structural degeneration across the whole brain, particularly affecting the thalamic, cerebellar, striatal, and superior longitudinal tracts and corpus callosum. Importantly, follow-up regression analyses in 72 predefined tracts showed that the decline in fiber density and cross-section from 3 months to 3 years was associated with worse cognitive performance at 3 years after stroke, especially affecting visuospatial processing, processing speed, language, and recognition memory.DiscussionWe conclude that white matter neurodegeneration in ipsi-and contralesional thalamic, striatal, and cerebellar tracts continues to be greater in stroke survivors compared with stroke-free controls. White matter degeneration persists even years after stroke and is associated with poststroke cognitive impairment.Trial Registration InformationClinicalTrails.gov NCT02205424.

Original languageEnglish
Pages (from-to)E1664-E1672
Number of pages10
JournalNeurology
Volume100
Issue number16
DOIs
Publication statusPublished - 18 Apr 2023

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