Patterns of white matter degeneration in remote brain areas from the basal ganglion lesion of ischemic stroke patients with motor impairment

Abstract

Background: Diffusion tensor imaging (DTI) studies have revealed distinct white matter characteristics of the brain following diseases. Beyond the lesion-symptom mapping, recent studies have demonstrated extensive structural and functional alterations of remote areas to local lesions caused by stroke in the brain. Here, we further investigated the structural changes from a global level using DTI data through multivariate pattern analysis (MVPA) and network-based statistic (NBS). Methods: Ten ischemic stroke patients with basal ganglia lesions and motor dysfunctions and eleven demographically matched adults as controls underwent brain Magnetic Resonance Imaging scans. DTI data were processed to obtain fractional anisotropy (FA) maps and MVPA was used to explore brain regions that play an important role in classification based on FA maps. The white matter (WM) structural network was constructed by the deterministic fiber tracking approach according to the Automated Anatomical Labeling (AAL) atlas. NBS was used to explore differences in structural networks between groups. Results: MVPA applied to FA images correctly identified stroke patients with a statistically significant accuracy of 100% (P≤0.001). Compared with the controls, the study patients showed FA reductions in the perilesional basal ganglia and brainstem, with a few showing reductions in bilateral frontal lobes. Using NBS, we found a significant decrease in FA-weighted WM subnetwork in stroke patients. Conclusions: We identified some patterns of WM degeneration affecting brain areas remote to the ischemic lesion, revealing the abnormal organization of WM network in stroke patients, which may be helpful for the understanding of the neural mechanisms of stroke sequela.