Total small vessel disease burden and brain network efficiency in cerebral amyloid angiopathy

BACKGROUND: Cerebral amyloid angiopathy (CAA) is associated with hemorrhagic and nonhemorrhagic markers small vessel disease (SVD). A composite score to quantify the total burden of SVD on MRI specifically for CAA patients was recently developed. Brain network alterations related to individual MRI markers of SVD in CAA were demonstrated. OBJECTIVES: Considering diffusion based network measures sensitive to detect different relevant SVD-related brain injury, we investigated if increased overall SVD injury on MRI corresponds to worse global brain connectivity in CAA. METHODS: Seventy-three patients (79.5% male, mean age 70.58±8.22years) with a diagnosis CAA were considered. SVD markers in total MRI SVD score included: lobar cerebral microbleeds, cortical superficial siderosis (cSS), white matter hyperintensities (WMH) and centrum semiovale-enlarged perivascular spaces. Diffusion imaging based network reconstruction was made. The associations between total MRI SVD score and global network efficiency (GNE) were analyzed. RESULTS: A modest significant inverse correlation between total MRI SVD score and GNE existed (p=0.013; R2=0.07). GNE was related with the presence of cSS and moderate-severe WMHs. CONCLUSIONS: An increased burden of SVD neuroimaging markers corresponds to more reductions in global brain connectivity, implying a possible cumulative effect of overall SVD markers on disrupted physiology. GNE was related with some components of the score, specifically cSS and moderate-severe WMHs.