Objective: We investigated whether severe, MRI-visible perivascular spaces (PVS) in the cerebral hemisphere white matter (centrum semiovale) are more common in patients with pathologyproven cerebral amyloid angiopathy (CAA) than in those with pathology-proven non-CAA-related intracerebral hemorrhage (ICH). Methods: Using a validated 4-point scale on axial T2-weighted MRI, we compared PVS in patients with pathology-proven CAA to PVS in those with spontaneous ICH but no histopathologic evidence of CAA. In a preliminary analysis restricted to patients with T2*-weighted gradient-recalled echo MRI, we also investigated whether including severe centrum semiovale PVS increases the sensitivity of existing diagnostic criteria for probable CAA. Results: Fourteen patients with CAA and 10 patients with non-CAA-related ICH were included. Eight of the patients with CAA were admitted for symptomatic, spontaneous lobar ICH, 1 because of ischemic stroke, 1 with transient focal neurologic episodes, and 4 due to cognitive decline. Severe (>20) centrum semiovale PVS were more frequent in patients with CAA compared to controls (12/14 [85.7%; 95% confidence interval (CI): 57.2%-98.2%] vs 0/10 [1-sided 95% CI: 0%-30.8%], p