Training labels for hippocampal segmentation based on the EADC-ADNI harmonized hippocampal protocol

Background: The European Alzheimer's Disease Consortium and Alzheimer's Disease Neuroimaging Initiative (ADNI) Harmonized Protocol (HarP) is a Delphi definition of manual hippocampal segmentation from magnetic resonance imaging (MRI) that can be used as the standard of truth to train new tracers, and to validate automated segmentation algorithms. Training requires large and representative data sets of segmented hippocampi. This work aims to produce a set of HarP labels for the proper training and certification of tracers and algorithms. Methods: Sixty-eight 1.5 T and 67 3 T volumetric structural ADNI scans from different subjects, balanced by age, medial temporal atrophy, and scanner manufacturer, were segmented by five qualified HarP tracers whose absolute interrater intraclass correlation coefficients were 0.953 and 0.975 (left and right). Labels were validated as HarP compliant through centralized quality check and correction. Results: Hippocampal volumes (mm3) were as follows: controls: left 5 3060 (standard deviation [SD], 502), right 5 3120 (SD, 897); mild cognitive impairment (MCI): left 5 2596 (SD, 447), right 5 2686 (SD, 473); and Alzheimer's disease (AD): left 5 2301 (SD, 492), right 5 2445 (SD, 525). Volumes significantly correlated with atrophy severity at Scheltens' scale (Spearman's r5 ,20.468, P5 ,.0005). Background: The European Alzheimer's Disease Consortium and Alzheimer's Disease Neuroimaging Initiative (ADNI) Harmonized Protocol (HarP) is a Delphi definition of manual hippocampal segmentation from magnetic resonance imaging (MRI) that can be used as the standard of truth to train new tracers, and to validate automated segmentation algorithms. Training requires large and representative data sets of segmented hippocampi. This work aims to produce a set of HarP labels for the proper training and certification of tracers and algorithms. Methods: Sixty-eight 1.5 T and 67 3 T volumetric structural ADNI scans from different subjects, balanced by age, medial temporal atrophy, and scanner manufacturer, were segmented by five qualified HarP tracers whose absolute interrater intraclass correlation coefficients were 0.953 and 0.975 (left and right). Labels were validated as HarP compliant through centralized quality check and correction. Results: Hippocampal volumes (mm³) were as follows: controls: left 5 3060 (standard deviation [SD], 502), right 5 3120 (SD, 897); mild cognitive impairment (MCI): left 5 2596 (SD, 447), right 5 2686 (SD, 473); and Alzheimer's disease (AD): left 5 2301 (SD, 492), right 5 2445 (SD, 525). Volumes significantly correlated with atrophy severity at Scheltens' scale (Spearman's r5 ,20.468, P5 ,.0005).