APOE and Atrophy: Factors such as the degree of memory impairment, altered levels of amyloid-β and tau-proteins in the cerebral fluid, and abnormal fluorodeoxyglucose (FDG) positron emission tomography (PET) together with APOE ɛ4 genotype and atrophy detected on magnetic resonance imaging (MRI), have been found to predict conversion from MCI to dementia (10, 11).