Brain Characterization of Amyloid Protein and Glucose Metabolism of ALFA Project Participants

18F-Flutemetamol scans will be categorized as either positive or negative according to the standardized uptake value ratio (a quantitative measurement based on a ratio of mean target cortex activity divided by that in a cerebellar reference region). Participants with a SUVr over 1.56 will be classified as positive and, otherwise, as negative.