Use of structural magnetic resonance imaging to predict who will get Alzheimer's disease

We used magnetic resonance imaging (MRI) measurements to determine whether persons in the prodromal phase of Alzheimer's disease (AD) could be accurat ely identified before they developed clinically diagnosed dementia. Normal subjects (n = 24) and those with mild memory difficulty (n = 79) received a n MRI scan at baseline and were then followed annually for 3 pears to deter mine which individuals subsequently met clinical criteria for AD. Patients with mild AD at baseline were also evaluated (n = 16). Nineteen of the 79 s ubjects with mild memory difficulty "converted" to a diagnosis of probable AD after 3 years of follow-up. Baseline MRI measures of the entorhinal cort ex, the banks of the superior temporal sulcus, and the anterior cingulate w ere most useful in discriminating the status of the subjects on follow-up e xamination. The accuracy of discrimination was related to the clinical simi larity between groups. One hundred percent (100%) of normal subjects and pa tients with mild AD could be discriminated from one another based on these MRT measures. When the normals were compared with the individuals with memo ry impairments who ultimately developed AD (the converters), the accuracy o f discrimination was 93%, based on the MRI measures at baseline (sensitivit y = 0.95; specificity = 0.90). The discrimination of the normal subjects an d the individuals with mild memory problems who did not progress to the poi nt where they met clinical criteria for probable AD over the 3 years of fol low-up (the "questionables") was 85% and the discrimination of the question ables and converters was 75%. The apolipoprotein E genotype did not improve the accuracy of discrimination. The specific regions selected for each of these discriminations provides information concerning the hierarchical fash ion in which the pathology of AD may affect the brain during its prodromal phase.