Background: This study aimed to understand the injury of white matter (WM) microstructure behind white matter hyperintensities (WMH) and identify the regions where injury was more pronounced with increasing WMH severity. Moreover, we analyzed whether this microstructural injury is related to cognition.
Methods: 110 patients with WMH were recruited in this research. All subjects underwent 3.0T MRI scans and neuropsychological cognitive assessments. Simple mental state examination (MMSE) along with Montreal Cognitive Assessment (MoCA) were applied to assess the patient's overall cognitive ability. WMH of each subject was graded according to Fazekas grade scale and was divided into two groups: (A) WMH score of 1-2 points (n=64), (b) WMH score of 3-6 points (n=46). Trace-based spatial statistics (TBSS) was applied for the analysis of diffusion tensor imaging (DTI) data. All statistical analyses were performed in SPSS 26.0 statistical software.
Results: The results indicate that patients with higher WMH scores showed extensively symmetrical areas of increased mean diffusion, axial diffusion and radial diffusion involving bilateral anterior limb, posterior limb and retrolenticular part of internal capsule, posterior corona radiata, external capsule, superior longitudinal fasciculus, and superior fronto-occipital fasciculus (P < 0.01).
Conclusions: Finally, we come to the conclusion that cognition-related WM fiber tracts tend to be more vulnerable to be injured in patients of cerebral small vessel disease (CSVD). Moreover, changes in WM microstructure often predate changes of cognition. Early detection of microstructural changes and timely intervention can delay cognitive decline to some extent.