Objective To determine whether preclinical Alzheimer disease (AD), as detected by the
amyloid-imaging agent Pittsburgh Compound B (PiB) in cognitively normal older adults, is
associated with risk of symptomatic AD. Design A longitudinal cohort study of cognitively
normal older adults assessed with positron emission tomography (PET) to determine the
mean cortical binding potential for PiB and followed up with annual clinical and cognitive
assessments for progression to very mild dementia of the Alzheimer type (DAT). Setting The …