Prisma fit 3t scanner

Blood oxygenated level dependent (BOLD) signal was acquired at the Unité de Neuroimagerie Fonctionnelle de l’Institut de Gériatrie de l’Université de Montréal on a Siemens Prisma Fit 3T scanner. Functional imaging data were acquired with a T2-weighed multiband echo planar imaging sequence (TR = 785 ms; TE = 30 ms; FA = 54°; matrix size 64 × 64, voxel size 3 mm³; 42 slices). Functional slices were oriented in transverse plane and were angled to be parallel to the AC-PC line. During EPI image acquisition, an inline retrospective motion correction algorithm was employed. During the same session, high-resolution T1-weighted anatomical images were acquired (TR = 2300 ms; TE = 2.98 ms; FA = 9°; matrix size=256 × 256; voxel size = 1 mm³; 176 slices).

Structural and diffusion-weighted images were acquired in a single session using a Siemens Prisma Fit 3 T scanner and a 32-channel head coil at the Donders Center for Cognitive Neuroimaging, Nijmegen. Diffusion weighted images were acquired with a simultaneous‐multislice diffusion‐weighted Echo Planar Imaging (EPI) sequence. Acquisition parameters were the following: multiband factor = 3; TR (repetition time) = 2282 ms; TE (echo time) = 71.2 ms; in-plane acceleration factor = 2; voxel size = 2 × 2 × 2 mm³; 9 unweighted scans; 100 diffusion-encoding gradient directions in multiple shells; b-values = 1250 and 2500 s/mm²; Taq (total acquisition time) = 8 min 29 s. A high-resolution T1 anatomical scan was obtained for spatial processing of the DWI data using the MP2RAGE sequence (Marques et al., 2010 (link)) with the following parameters: 176 slices, voxel size = 1 × 1 × 1 mm³, TR = 6 s, TE = 2.34 ms, Taq = 7 min 32 s.

Motion was restricted by using padding around the head, arms, and body. While all data were acquired using the same Siemens Prisma Fit 3 T scanner, the exact parameters used for MPRAGE acquisition varied between studies (see Supplementary Table S1). Scan variability can be mitigated with inclusion of study as a covariate (Fennema-notestine et al., 2007 (link); Pardoe et al., 2008 ; Chen et al., 2014 (link); Takao et al., 2014 (link)), therefore, study number was included as a control variable in all statistical models.

All patients and HCs had the same structural MRI sequences obtained in a Siemens (Siemens Healthcare, Erlangen, Germany) Prisma^fit 3T scanner. The protocol included a 3-dimensional (3D) T₁-weighted multi-echo magnetization-prepared rapid gradient echo (MEMPRAGE: 1 mm × 1 mm × 1 mm voxel size), axial 3D fluid-attenuated inversion recovery (FLAIR) (0.9 mm × 0.9 mm × 0.9 mm voxel size) and high-resolution susceptibility-weighted imaging (SWI: 0.9 mm × 0.9 mm × 1.4 mm voxel size) sequences.
All MRI sequences were reviewed to identify the presence of ICH, the number of lobar CMBs, and the presence and extent of cSS based on established criteria (Greenberg et al., 2009 (link); Charidimou et al., 2015 (link)). Lacunes and cortical CMI were also identified using previously defined criteria (Wardlaw et al., 2013 (link); van Veluw et al., 2016 (link); Gokcal et al., 2021 (link)). None of the HCs had any hemorrhagic marker of cSVD (ICH, CMBs, or cSS) on MRI. Average cortical thickness (CTh), WMH volume, white matter volume (WMV), and estimated total intracranial volume (eTIV) were calculated using the FreeSurfer software suite (v7.1.1).¹ WMH and WMV were expressed as a percent of eTIV (pWMH and pWMV, respectively) to correct the measurements for the variable head size of the participants. In patients with ICH, the volume estimates of the ICH-free hemispheres were used and multiplied by 2.