Florbetapir F 18 is an experimental radioactive drug that may allow doctors to image changes in the brain using a PET (Positron Emission Tomography) scanner. The purpose of this study is to evaluate the imaging characteristics of, Florbetapir F 18 (also known as 18F-AV-45) in patients who have previously undergone bleeding in their brains. Florbetapir F 18 binds to amyloid-ß peptide (Aß) that accumulates in the brains of patients with bleeding. These accumulations are called amyloid plaques and when extensive are labeled cerebral amyloid angiopathy (CAA). Florbetapir F 18 sticks to the amyloid plaques in the brain and emits a low level of gamma rays which can be detected by a PET camera.