Comparison of automated and manual MRI volumetry of hippocampus in normal aging and dementia

PURPOSE: To determine whether automatic and manual measurements of hippocampal volume differences on MRI between normal aging, cognitive impairment (CI), and Alzheimer's disease (AD) yield similar results. MATERIALS AND METHODS: Reliability was determined for an automatic and a manual method on nine volunteers (22-83 years old) who underwent MRI twice in 1 day. Hippocampal volumes of 20 cognitively normal subjects (mean age 74.0 +/- 6.2 years) and age-matched patients (20 CI and 20 AD) were compared. RESULTS: The intraclass correlation for automatic calculations of hippocampal volume was 0.94; for manual tracing it was 0.99. Volume differences between cognitively normal, CI, and AD subjects from the automatic and manual methods were similar. CONCLUSION: Because the automatic calculations were faster and less susceptible to rater bias than manual tracing, this automated method is expected to be very useful for analyzing hippocampal changes in studies of aging and dementia.