Magnetom trio mri system

Participants were scanned on a 3.0 T Siemens Magnetom Trio MRI system (Erlangen, Germany) using a 12 channel head coil. Whole brain diffusion tensor imaging was acquired with the following parameters: FOV = 240 × 240 mm; 72 slices, slice thickness = 2 mm; TE = 98 ms; TR = 10,000 ms; in-plane resolution = 1.875 × 1.875 mm; diffusion encoding directions = 30; b = 0 s/mm² and 1,000 s/mm². Data were processed using the University of Oxford’s Center for Functional Magnetic Resonance Imaging of the Brain (FMRIB) Software Library (FSL) release 5.0 (22 (link)) diffusion toolbox (FDT) (23 (link),24 (link)). Eddy current correction was accomplished using the eddy_correct tool and a diffusion tensor model was fit in each voxel using the DTIFIT tool, which generates fractional anisotropy (FA) values in every voxel. FA images were further processed using the FSL tract-based spatial statistics (TBSS) (25 (link)) toolbox, which projects each subjects’ FA data onto a mean white matter skeleton, representing the white-matter tracts common to all subjects.
Mean FA within the white matter skeleton for specific regions of interest were calculated for each subject using the JHU ICBM DTI-81 atlas (26 (link)). The regions of interest are listed in Table 1.

Participants lay supine in the scanner with the response pad under their right hands. The visual stimuli were projected onto a projection screen situated behind the participant’s head and were visible via a mirror. Earplugs were used to muffle the scanner noise. A PC running Cogent 2000 via MATLAB controlled the presentation of the visual paradigm and recorded the participants’ responses.
A 3 Tesla Siemens Magnetom Trio MRI system was used for fMRI acquisition. The participants’ heads were immobilized with calipers built into the head-coil. High-resolution T1-weighted anatomical scans were obtained (Time to Repeat (TR): 2600, Time to Echo (TE): 3.02, Field of View (FOV): 256 mm, matrix: 256 × 256 and slice thickness: 1.00 mm). Functional scans were acquired in the axial plane using 46 3-mm slices with a 0-mm gap (TR: 2500, TE: 28, Matrix: 64 × 64, FOV: 192 mm, voxel size: 3 × 3 × 3 mm).
We obtained 136 TRs in each session. For all functional sessions, the first five images were excluded from the data for stabilization of the MR signal. There were four functional runs; as such, the data analyzed consisted of 524 images.

MRI examinations were performed on a three Tesla Magnetom Trio MRI system (Siemens Medical Solutions, Germany). T1‐weighted images: axial images were acquired before and after contrast agent injection (gadopentetate‐dimeglumine, Magnevist, Bayer Schering Pharma AG). Repetition time 600 ms; echo time 12 ms; slice thickness 5 mm; interslice distance 1 mm; in‐plane resolution 0.45:0.45 mm; matrix size 384:512; and 23 slices. T2‐weighted images: axial images with repetition time 10 seconds, echo time 70 ms, slice thickness 5 mm, interslice distance 1 mm, in‐plane resolution 0.60:0.45 mm, matrix size 384:512 and 23 slices. Dynamic contrast‐enhanced images: axial, fast gradient‐echo images with repetition time 5.7 ms, echo time 2.73 ms, slice thickness 2.1 mm, interslice distance 0.4 mm, in‐plane resolution 2.90:2.00 mm, matrix size 128:87 and 20 slices. After approximately 52 seconds of imaging, a 0.1 mmol/kg dose of Gd‐DTPA was injected at 5 cc/s. Spoiled gradient recalled‐echo images with five different flip angles (2°, 5°, 10°, 15° and 30°) were also initially acquired for T1 mapping.