Cerebral microhemorrhage and brain β-amyloid in aging and Alzheimer disease.

Incidental cerebral microhemorrhage (MH) is frequently found in older individuals scanned with susceptibility-weighted MRI (SWI) or gradient-recalled echo MRI. MH have been linked with β-amyloid (Aβ) deposition using (11)C-Pittsburgh compound B (PiB) PET in Alzheimer disease (AD) and cerebral amyloid angiopathy (CAA). We hypothesized that Aβ deposition in asymptomatic elderly individuals is associated with lobar MH (LMH).