Pervasive White Matter Fiber Degeneration in Ischemic Stroke

Abstract

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.

Fibre-specific laterality of white matter in left and right language dominant people

“…Taking all of this into account, it might thus be advisable to even avoid the brain flipping strategy altogether in such studies, and rather analyse both patient groups separately. The latter approach was for example taken by Egorova et al (2020), who compared left and right side infarcted stroke groups separately to controls, to allow for greater specificity in results.…”

“…Even though FBA is a relatively recently developed method, it has proven to be a favourable technique to examine white matter properties in several studies. It has already been used in a range of different clinical groups (including Parkinson's disease (Rau et al, 2019), traumatic brain injury (Verhelst et al, 2019), stroke (Egorova et al, 2020), multiple sclerosis (Gajamange et al, 2018), depression (Lyon et al, 2019), autism spectrum disorder (Dimond et al, 2019), and Alzheimer's disease (Mito et al, 2018)) and in healthy cohorts (Choy et al, 2020;Dimond et al, 2020;Genc et al, 2018).…”

Relevance of Porcine Stroke Models to Bridge the Gap from Pre-Clinical Findings to Clinical Implementation

“…WM injuries are normally found in elderly people in the general population [ 34 , 35 ]. In strokes caused by the occlusion of large cerebral vessels, WM axonal fibers are often affected [ 36 , 37 , 38 ]. WM damage with axon degeneration has been found in post-mortem human brains from ischemic stroke patients [ 39 , 40 ].…”

Characterizing white matter alterations in drug-naïve de novo Parkinson’s disease with diffusion MRI

“…In contrast to conventional voxel-based analysis with DTI measures, which fails to handle fiber-crossing within voxels, FBA allows more interpretable results by identifying specific fiber tracts that are relevant to the designated study. Since its debut, this technique has demonstrated good specificity, sensitivity, and reliability in various applications, including natural aging (Choy et al ., 2020), Alzheimer’s disease (Mito et al ., 2018), stroke (Egorova et al ., 2020), traumatic brain injury (Wallace et al ., 2020), and mental disorders (Lyon et al ., 2019).…”