Standard 12 channel head matrix coil

A standard 3 T whole-body MR system with transmit body coil was used (MAGNETOM Trio, A Tim System, upgraded during the study to a MAGNETOM PRISMA, Siemens Healthcare, Germany) in conjunction with either a standard 12-channel head matrix coil (Siemens Healthcare, Germany), four channel carotid artery coil (Rapid Biomedical, Germany) or single-channel loop coil (4 cm diameter, Siemens). No water or fat suppression schemes were used.

Data were collected on a 3T Siemens Trio MRI scanner using the standard 12-channel head matrix coil (Siemens, Malvern, PA). Functional images were acquired with a t2*-weighted gradient echo EPI sequence (30 interleaved axial slices, phase encoding P to A, 3 × 3 mm voxels, slice thickness = 4 mm; 128 × 128 matrix; 230 mm FOV; TR = 2100 ms, TE = 31 ms, Flip Angle: 78°; 145 whole-brain volumes). After functional scans, a high resolution whole-brain structural image was acquired (MPRAGE sequence, 1 mm isotropic voxels, FOV = 160 × 256 × 256 mm, Flip Angle: 9°).
Data were processed with FSL (FMRIB’s Software Library, www.fmrib.ox.ac.uk/fsl). Brain extraction was performed using the FSL Brain Extraction Tool (Smith, 2002 (link)). Data was high-pass filtered with a cutoff frequency of 100 Hz and spatially smoothed with a 5 mm FWHM Gaussian kernel filter.