Automated algorithm to measure changes in medial temporal lobe volume in Alzheimer disease

•Fully automated medial temporal lobe (MTL) atrophy measurement.•Significant MTL atrophy over 24 months in NEC, MCI, and AD groups.•A significant difference in MTL atrophy detected between MCI and AD groups.•A significant association between MTL atrophy and decline in cognition.•Volume changes in MTL may help predict AD progression. The change in volume of anatomic structures is as a sensitive indicator of Alzheimer disease (AD) progression. Although several methods are available to measure brain volumes, improvements in speed and automation are required. Our objective was to develop a fully automated, fast, and reliable approach to measure change in medial temporal lobe (MTL) volume, including primarily hippocampus. The MTL volume defined in an atlas image was propagated onto each baseline image and a level set algorithm was applied to refine the shape and smooth the boundary. The MTL of the baseline image was then mapped onto the corresponding follow-up image to measure volume change (ΔMTL). Baseline and 24 months 3D T1-weighted images from the Alzheimer Disease Neuroimaging Initiative (ADNI) were randomly selected for 50 normal elderly controls (NECs), 50 subjects with mild cognitive impairment (MCI) and 50 subjects with AD to test the algorithm. The method was compared to the FreeSurfer segmentation tools. The average ΔMTL (mean±SEM) was 68±35mm3 in NEC, 187±38mm3 in MCI and 300±34mm3 in the AD group and was significantly different (p