Cerebral microinfarcts disruption of remote cortical thickness

Introduction: Cerebral microinfarcts (CMI) are common lesions, carrying an important contribution to small-vessel-related cognitive impairment. CMIs were previously found to cause local microstructural damage and disruption of white matter integrity. This study examines CMIs influence on cortical thickness in remote brain areas.

Methods: Six small silent diffuse weighted imaging (DWI) lesions corresponding to subacute CMI were identified among five patients who underwent baseline and follow-up MRI scans from the Tel-Aviv Acute Brain Stroke Cohort (TABASCO). Regions of interest (ROIs) corresponding to the site of the DWI lesions and of the non-lesioned contralateral hemisphere (control ROI) were co-registered. DTI tractography was additionally performed to reconstruct the white matter tracts containing the ROIs. The normalized cortical thickness was calculated for the DWI lesional tract as well as for the contralateral non-lesional tract, and the lesion-to-control cortical thickness ratio (CTR) was calculated.

Results: Post-lesional scans, performed 25.1 ± 1.2 months after CMI detection, demonstrated reduced mean CTR within the ROI from 1.8 to 1.1 (p = 0.032). There was no difference between the CTR of the right hemisphere relative to those on the left hemisphere, or between the CTR change of the cortical and non-cortical CMI.

Discussion: This study demonstrated the prolonged influence of CMI on cortical thickness in remote ROI. The total number of CMIs is difficult to determine, however it has been shown that detecting even a single CMI suggests the existence of hundreds to thousands lesions. Therefore, the cumulative impact of these widely distributed lesions on cerebral cortex may have a significant contribution to the development of vascular cognitive impairment.