Sc72 gradient coil

High quality structural and dMRI data of 100 healthy subjects (males = 46, females = 54 age range 22–36 years) were collected from the HCP repository in minimally pre-processed form [36 (link)]. Data were acquired by the Washington University, University of Minnesota, and Oxford University (WU-Minn) HCP Consortium [37 (link)]. All subjects were scanned using a Siemens 3T Skyra scanner previously modified with a Siemens SC72 gradient coil and a stronger gradient power supply, with a maximum gradient amplitude (Gmax) of 100 mT/m (initially 70 mT/m and 84 mT/m in the pilot phase), with the aim of improving diffusion imaging. Diffusion-weighted images (DWI) were acquired using a single-shot 2D spin-echo multiband Echo Planar Imaging (EPI) sequence and equally distributed over 3 shells (b-values of 1000 s/mm², 2000 s/mm² and 3000 s/mm²), with an isotropic spatial resolution of 1.25 mm. [38 (link)]. The structural scans included T1-weighted acquisitions with the following parameters: echo time (TE) = 2.14 ms, time repetition (TR) = 2400 ms, voxel size = 0.7 mm. [39 (link)].

MRI acquisitions were carried out using a custom‐made Siemens 3T “Connectome Skyra” (Siemens, Erlangen, Germany), provided with a Siemens SC72 gradient coil and stronger gradient power supply with maximum gradient amplitude (Gmax) of 100 mT/m (initially 70 and 84 mT/m in the pilot phase), which allows improvement of diffusion‐weighted imaging (DWI).
High‐resolution T1‐weighted MPRAGE images were collected using the subsequent parameters: voxel size = 0.7 mm, TE = 2.14 ms, TR = 2400 ms (Van Essen et al., 2012). DWIs were acquired using a single‐shot 2D spin‐echo multiband Echo Planar Imaging sequence and equally distributed over three shells(b‐values 1,000; 2,000; 3,000 mm/s²), 90 directions per shell, spatial isotropic resolution of 1.25 mm (Sotiropoulos et al., 2013). More details about experimental setup and preprocessing pipelines are described elsewhere (Glasser et al., 2013; Glasser et al., 2016; Sotiropoulos et al., 2013; van Essen et al., 2012).

HCP data were acquired with a 32-channel head coil on a Siemens 3T Skyra modified to include a Siemens SC72 gradient coil to achieve a maximum gradient strength of 100 mT/m. Whole brain images were acquired using echo-planar imaging (EPI) with the following parameters: repetition time (TR) = 720 ms, echo time (TE) = 33.1 ms, flip angle = 52°, BW = 2290 Hz/Px, in-plan FOV = 208 x 180 mm, 72 slices, 2 mm isotropic voxels, with a multi-band acceleration factor of 8. For each task, there were two runs, one with right-to-left phase encoding and one with left-to-right phase encoding to minimize signal dropout in the combined results. Details of scanner modifications and data acquisition parameters are further described in Ugurbil et al. [37 (link)].