3t trio mri

Fifteen healthy controls (8 males; mean age 10.2 years ± 3.1; range 4–14) completed MR imaging at the Boston Children’s Hospital, Boston, MA, USA. MR acquisitions were performed on a Siemens 3T Trio MRI. Diffusion scans were acquired using a multi-direction (n = 90) and multi-b-value scheme ranging from 400 to 3000 s/mm² according to the Cube and Sphere (CUSP) gradient set of Scherrer and Warfield (2012) (link) (12 at b = 0 s/mm², 6 at b = 400 s/mm², 6 at b = 600 s/mm², 6 at b = 800 s/mm², 30 at b = 1000 s/mm² and 30 gradients on the cube of constant TE, with b-values in the interval 1000 < b < 3000 s/mm²). Other acquisition parameters were: 128 ± 128 matrix, FOV 220 mm, TR/TE: 5700/89 ms, 1.7 × 1.7 × 2 mm³. Eddy currents were minimized by using a twice refocused spin echo sequence (Reese et al., 2003 (link)). An anatomical T1-weighted 1 mm isotropic MPRAGE image was also acquired for each subject (256 × 256 matrix, FOV 200–256 mm, TR/TE 2530/3.54 ms). The study was approved by the Institutional Review Board and all participants provided informed consent. Finally, a separate HCP dMRI dataset with an isotropic voxel size of 1.25 mm was also analysed. Only the b = 3000 s/mm² shell with 90 diffusion directions was used.

T1-weighted MPRAGE (176 slices, voxel size =1.0 x 1.0 x 1.0 mm, TR =1900 msec, TE =2.52 msec, and FoV =256 mm) and DTI (64 directions, 60 slices, voxel size =2.0 x 2.0 × 2.0 mm, TR =9000 msec, TE =99 msec, FoV =220 mm, and b =1100 s/mm²) scans were collected using a Siemens 3T Trio MRI with a 32-channel head coil.

All MRI data were acquired on a 3T Trio MRI (Siemens Medical Solutions, Erlangen, Germany). Images were acquired using a body coil for transmission and a 12-element coil for reception. In addition to the diffusion data, T2- (T2w) and T1-weighted (T1w) images were acquired and used for clinical evaluation of gross brain abnormalities in each subject. In addition, a field map image coplanar to the diffusion acquisition was acquired using a pair of non-EPI gradient echo images at two echo times and employed to correct for image distortions from B0 field inhomogeneities.
Diffusion imaging data were acquired using a diffusion-weighted spin-echo Echo Planar Imaging sequence (EPI) for a total of 64 uniformly distributed gradient directions and for two b values (b = 1000 and 2000 s/mm²). Ten non-weighted diffusion images (b=0 s/mm²) were also collected. Other image parameters included: 55 contiguous slices, isotropic voxel size of 2.3x2.3x2.3 mm³, TR = 8s, TE = 97ms, parallel imaging with an acceleration factor of 2, and a phase partial Fourier factor of 6/8.
Anatomical T1w data were acquired using a magnetization prepared rapid gradient-echo (MPRAGE) sequence with resolution of 1x1x1mm³ resolution, TR=2300ms, TE=2.98ms, TI=900ms, and a flip angle of 9°.

Imaging data was collected using a Siemens 3T TRIO MRI (Erlangen, Germany), running VB17 software and equipped with a 32-channel RF head coil. DTI data was collected using a spin-echo, EPI sequence with a spatial resolution of 1.7×1.7×3.0 mm. The sequence parameters were: TE/TR=87/8000 ms, FOV=200 mm, axial slice orientation with 50 slices and no gaps, 64 isotropically distributed diffusion weighted directions, two diffusion weighting values (b=0 and 700 s/mm²) and five b=0 images. Subjects’ head movement was minimized with restraining padding.

All imaging was performed at the University of Maryland Center for Brain Imaging Research using a Siemens 3T TRIO MRI (Erlangen, Germany) system and 32-channel phase-array head coil. Three white-matter-related imaging protocols were applied to each subject: high-angular resolution diffusion imaging (HARDI) DTI for FA, 3D FLAIR for HWM, and multi b-value diffusion imaging (MBI) for PDI.

All imaging was performed using a Siemens 3T TRIO MRI (Erlangen, Germany) system equipped with a 32-channel phase array head coil. Participants were scanned prior to TMS assessment. A high resolution T1-weighted image (0.8 mm isotropic) was obtained (TE/TR/TI=3.04/2100/785 ms, flip angle=11 degrees) for TMS localization. The structural images were aligned to anterior commissure-posterior commissure line (AC-PC). DTI data were collected using a single-shot, echo-planar, single refocusing spin-echo, T2-weighted sequence at 1.7×1.7×3.0 mm, TE/TR=87/8000ms, FOV=220mm, 50 slices and no gaps, five interleaved (every 10 volumes) b=0 volumes and 64 non-colinear distributed diffusion weighted directions with b=700 s/mm² [62 (link)]. These sequence parameters were calculated using an optimization technique that maximizes the contrast to noise ratio for FA measurements [63 (link)].