Effects of age and Alzheimer's disease on hippocampal subfields: comparison between manual and FreeSurfer volumetry: Hippocampal Subfields Volumetry

International audienceGrowing interest has developed in hippocampal subfield volumetry over the past few years and an increasing number of studies use the automatic segmentation algorithm implemented in FreeSurfer. However, this approach has not been validated on standard resolution T1-weighted MR as used in most studies. We aimed at comparing hippocampal subfield segmentation using FreeSurfer on standard T1-weighted images versus manual delineation on dedicated high-resolution hippocampal scans. Hippocampal subfields were segmented in 133 individuals including 98 cognitively normal controls aged 19 to 84 years, 17 mild cognitive impairment (MCI) and 18 Alzheimer's disease (AD) patients using both methods. Intraclass correlation coefficients (ICC) and Bland-Altman plots were computed to assess the consistency between both methods, and the effects of age and diagnosis were assessed from both measures. Low to moderate ICC (0.31 to 0.74) were found for the subiculum and other subfields as well as for the whole hippocampus, and the correlations were very low for CA1 (