Impact of Cerebral Microbleeds on White Matter Microstructures in Ischemic Cerebral Vascular Disease: A Diffusion Tensor Imaging Study

摘要

Cerebral microbleed (CMB) is a neuroimaging marker for cerebral small vessel disease (CSVD), which is an important risk factor for pathological aging. Diffusion Tensor Imaging (DTI) may provide new insights to the influence pattern of CMB on white matter and its relationship with otherCSVD imaging markers. 117 consecutive non-demented old people of mild symptoms of ischemic cerebral vascular disease were prospectively recruited and then divided into CMB negative and positive group according to CMB presence. Conventional MRI and DTI scanning were performed, and global cognitivefunction was evaluated for each participant. Two models of whole-brain voxel-based tractography-based spatial statistics (TBSS) which was adjusted by age, gender, education level and lacunar infarct number (model 1) and by age, gender, education level, lacunar infarct number, and white matterhyperintensity (model 2) were used to study the DTI metric changes in each participant. Significant reduction of FA and increase of MD, DR and DA were observed in two hemispheres in model 1. Affected white matter showed an obvious right lateralized involvement of right superior longitudinalfasciculus and association fibers in right frontal and parietal lobes, splenium and genu of corpus callosum, bilateral posterior and right anterior corona radiata. These DTI metric changes were significantly correlated with MMSE scores. Our study demonstrated for the first time that therewas a right lateralized asymmetry of CMB-related white matter microstructure injury, and this might be the structural basis of CSVD's deterioration effect on brain. The impact of CMB was closely related with white matter hyperintensity degree rather than lacunar infarct number. CMB detectionmaybe an important biomarker for future cognitive study and its influence to cognitive dysfunction should be considered in future study design.