Spatial Relation Between Microbleeds and Amyloid Deposits in Amyloid Angiopathy

Advanced cerebrovascular beta-amyloid deposition (cerebral amyloid angiopathy, CAA) is associated with cerebral microbleeds, but the precise relationship between CAA burden and microbleeds is undefined. We used T2(star)-weighted magnetic resonance imaging (MRI) and noninvasive amyloid imaging with Pittsburgh Compound B (PiB) to analyze the spatial relationship between CAA and microbleeds. On coregistered positron emission tomography (PET) and MRI images, PiB retention was increased at microbleed sites compared to simulated control lesions (p = 0.002) and declined with increasing distance from the microbleed (p < 0.0001). These findings indicate that microbleeds occur preferentially in local regions of concentrated amyloid and support therapeutic strategies aimed at reducing vascular amyloid deposition. ANN NEUROL 2010;68:545-548