Age effect on subcortical structures in healthy adults.

Cross-sectional age effects in normal control volunteers were investigated using magnetic resonance imaging in the following eight subcortical structures: lateral ventricles, thalamus, caudate, putamen, pallidum, hippocampus, amygdala and nucleus accumbens. Two hundred and twenty-six control subjects, ranging in age from 19 to 85 years, were scanned on a 1.5 T GE system (n=184) or a 3.0 T Siemens system (n=42). Volumes of subcortical structures, adjusted for cranium size, were estimated using FSL's FIRST software, which is fully automated. Significant age effects were found for all volumes when the entire age range was analyzed; however, the older subjects (60-85 years of age) showed a stronger correlation between age and structural volume for the ventricles, hippocampus, amygdala and accumbens than middle-aged (35-60 years of age) subjects. Middle-aged subjects were studied at both sites, and age effects in these groups were comparable, despite differences in magnet strength and acquisition systems. This agreement lends support to the validity of the image-analysis tools and procedures used in the present study.