Abstract

Background: One of the most reliable biomarkers of Alzheimer’s Disease (AD) is hippocampal atrophy demonstrated by MRI. Based on neuropathological data showing a differential vulnerability of hippocampal subfields to AD processes, hippocampal subfield analysis could improve the diagnostic accuracy of AD or Mild Cognitive Impairment (MCI). The objective of this study was to demonstrate the difference of hippocampal subfield volumes by using automated analysis for discriminating between AD, MCI and Healthy Controls (HC).
Material and Methods: Fifty-three age-matched subjects including 15 AD (mean 72.3 ± 6.9 years), 9 MCI (mean 68.4 ± 3.9 years) and 29 HC (mean 69.5 ± 5.1 years) were recruited and underwent MRI (3-Tesla) with highresolution 3D-T1W. Quantitative volumetric analysis of hippocampal subfields was performed by using Freesurfer (v. 6.0) for comparing AD, MCI and HC subjects.
Results: There was a widespread pattern of subfield atrophy. Right subiculum, right presubiculum, bilateral molecular layer, and bilateral fimbria volumes were higher diagnostic efficacy than whole hippocampal volume for discriminating AD subjects from HC or MCI subjects. Only left fimbria volume was significantly reduced in MCI subjects compared to HC (normalized volume 47.7, sensitivity=66.7%, specificity=89.7%, AUC 0.709). The accuracy of left fimbria as the predictor of positive amyloid PET MCI was 75%.
Conclusion: The structural brain imaging using quantitative volumetric analysis of hippocampal subfield could be used for differentiating AD, MCI and HC. These findings may be helpful for early detection and follow up of AD and MCI patients in the clinical setting.

Keywords: Alzheimer’s disease; Mild cognitive impairment; Hippocampal subfield volume; Amyloid PET