Impact and sonata

Before 2008, brain MRI was performed on 1.0 and 1.5T MRI systems (Siemens Magnetom Avanto, Vision, Impact and Sonata, GE Healthcare Signa HDXT). From 2008 on, MRI of the brain was performed on 3T MRI systems (MR750, GE Medical Systems, Ingenuity TF PET/MR, Philips Medical Systems; Titan, Toshiba Medical Systems). The standard dementia protocol with whole brain coverage included near-isotropic sagittal 3D T1-weighted images (including oblique coronal reconstructions), sagittal 3D T2-weighted fluid-attenuated inversion recovery (FLAIR) (including axial reconstructions), axial T2-weighted turbo spin-echo, and axial T2*-weighted gradient echo sequence or alternatively SWI sequences. MRI data was available for 432 (90%) individuals.
Bilateral hippocampal volume (HCV, mL) was estimated using FMRIBs Integrated Registration and Segmentation Tool (FIRST) [29 (link)]. Normalized brain volumes (NWBV, mL) were estimated with SIENAX (Structural Image Evaluation using Normalization of Atrophy Cross-sectional) using optimized settings [30 (link)]. Additionally, visual rating of MRI was performed according to semi-quantitative visual rating scales for medial temporal lobe atrophy (MTA, 0–4) and global cortical atrophy (GCA, 0–3) [31 (link), 32 (link)].

Scans before 2008 were performed on 1.0 and 1.5 Tesla scanners (Siemens Magnetom Avanto, Vision, Impact and Sonata, GE Healthcare Signa HDXT). From 2008 and on, MRI of the brain was performed on 3 T scanners (MR750, GE Medical Systems, Milwaukee, WI, USA; Ingenuity TF PET/MR, Philips Medical Systems, Best, The Netherlands; Titan, Toshiba Medical Systems, Japan). All images were performed according to a standardized protocol [23 (link)], of which we only used sagittal 3D T1-weighted images with coronal reformats in this study. All scans were reviewed by experienced neuroradiologists. We quantified left and right hippocampal volumes (HCV, mL) using FSL FIRST (FMRIBs Integrated registration and segmentation tool), which were summed for analysis [24 (link)].