Hippocampal atrophy in persons with age-associated memory impairment: volumetry within a common space.

OBJECTIVE The objective of this study is to demonstrate the assessment of hippocampal atrophy within a standard brain atlas for persons with age-associated memory impairment (AAMI) compared with cognitively intact elderly. METHODS High-resolution three-dimensional (3D) brain magnetic resonance imaging (MRI) was performed on 20 nondemented persons: 10 had AAMI and 10 were normal elderly. Scans were aligned to a common atlas template to control for errors due to variable brain size and orientation as well as facilitating communication of results across centers. Manual outlining every 1 mm with volumes determined for both the hippocampal head and body was accomplished after coronal resampling perpendicular to the long axis of the hippocampus. RESULTS Subject groups were similar in age, sex ratios, and educational achievement. The AAMI group had significantly lower volumes for the right hippocampus and hippocampal head (p =.02) compared with controls. CONCLUSION A growing body of work suggests the right hippocampal head as an early site of atrophy in early memory impairment. Subtle atrophic changes are detectable within a common atlas template allowing imaging assessment across centers.