Multimodal MRI Biomarkers in Alzheimer's Disease

Patients with AD underwent whole-brain MRI (3T DISCOVERY 750; GE) as part of the clinical assessment. First, trans-axial T2-weighted scans (TR/TE = 1130/80 ms, NEX = 2, voxel size = 0.55 × 0.55 × 10 mm³), 3D fluid-attenuated inversion recovery (FLAIR) images (TR/TE = 6000/126 ms, inversion time = 1861 ms, NEX = 1, voxel size = 0.56 × 0.56 × 1 mm³), and high-resolution sagittal T1-weighted images (TR/TE = 9.1/3.7 ms, NEX = 1, voxel size = 0.5 × 0.5 × 1.0 mm³) were acquired. The image analysis and rating procedure has been described in detail previously^{11 (link)}. In short, image analysis included the visual rating of MTA and PA on T1-weighted images. The MTA in the hippocampus was rated using a 5-point scale^{50 (link)}. PA in the posterior cingulate, parieto-occipital region, and precuneus was rated using a 4-point scale^{51 (link)}. Mean MTA and PA scores were calculated for both hemispheres. WMH was evaluated using a scale of age-related white matter change (ARWMC) on axial T2-weighted and 3D-FLAIR images^{52 (link)}. The 4-point ARWMC scale rates WMH in five brain regions per hemisphere.