The purpose of this research study is to evaluate the structure and function of the brain in healthy aging and early Alzheimer's disease using positron emission tomography (PET), magnetic resonance imaging (MRI), and computed tomography (CT) imaging. The study involves imaging the brain to detect the presence of amyloid deposits (plaques in the brain). Amyloid is a protein that may be related to dementia of Alzheimer's disease (DAT).~This study will use radioactive tracers called C-11 Pittsburgh Compound B (PIB) and F 18/ AV-1451 (Flortaucipir) which binds to beta amyloid and tau in the brain. These compounds are considered investigational, which means that they have not been approved by the United States Food and Drug Administration (FDA).
To identify factors that signal the transition from asymptomatic (preclinical) to symptomatic Alzheimer disease (AD).