Discriminative Analysis of Mild Alzheimer's Disease and Normal Aging Using Volume of Hippocampal Subfields and Hippocampal Mean Diffusivity: An In Vivo Magnetic Resonance Imaging Study

Background: Studies discovered that the hippocampal subfields are differentially affected by pathological damage, and magnetic resonance (MR) diffusion tensor imaging parameters might be more sensitive measures of early degeneration in Alzheimer's disease (AD) than conventional MR imaging techniques. The purpose of this study was to evaluate the significance of the volume of hippocampal subfields and the mean diffusivity (MD) value of hippocampus in discrimination between mild AD and normal aging. Methods: A total of 29 patients with mild AD and 30 normal aging were scanned. Binary logistic regression analysis was applied to assess the diagnostic significance of the volumes of hippocampal subfields and the MD value of hippocampus. Results: All hippocampal subfields except right tail atrophied significantly in the mild AD group (P < .05). The relative volumes of right CA1 and subiculum subfields entered the binary logistic regression model. The accuracy was 91.8%, which was improved to 93.9% as the MD value of right hippocampus entered the model. Conclusion: Atrophy was present in almost all hippocampal subfields at mild AD stage. The volumes of CA1 and subiculum were of the most diagnostic significance in discrimination of mild AD, which can be improved by the combination of volume and diffusivity analysis.