Nondemented older adult (>60 years) volunteers of known Alzheimer's Disease Assessment Scale (ADAS-Cog11), Mini-Mental State Examination (MMSE) and Consortium to Establish a Registry for Alzheimer's Disease (CERAD) neurocognitive test scores, ApolipoproteinE (APOE) e4 +/− cerebral amyloid PET status were prospectively recruited for 3T sodium-MRI brain scans. This evidence concerns the gene APOE and early-onset autosomal dominant Alzheimer disease.