Cerebral structure on MRI, Part I: Localization of age-related changes.

In this report, earlier findings of age-related changes in brain morphology on magnetic resonance (MR) images are extended to include measurements of individual cerebral grey matter structures and an index of white matter degeneration. Volumes of caudate, lenticular, and diencephalic structures are estimated, as are grey matter volumes in eight separate cortical regions. Results suggest that between 30 and 79 years significant decreases occur in the volume of the caudate nucleus, in anterior diencephalic structures, and in the grey matter of most cortical regions. The data suggest that the volumes of the thalamus and the anterior cingulate cortex may be unchanged. Among those cortical regions found to be affected in aging, some evidence is present for greater change in association cortices and mesial temporal lobe structures. There are also dramatic age-related changes in the white matter, manifest as lengthened T2 values on MR images.