Allegra mri scanner

Data were collected on a 3T Siemens Allegra MRI scanner at the University of Oregon’s Robert and Beverly Lewis Center for Neuroimaging. The task described here involved 4 functional runs of T2*-weighted blood oxygenation level dependent echo-planar images (BOLD-EPI; TR = 2000 ms; TE = 30 ms; flip angle = 80°; matrix size = 64 x 64; 32 axial slices with interleaved acquisition; slice thickness = 4mm; field of view = 200 mm; in-plane resolution = 3.125 x 3.125 mm; bandwidth = 2605 Hz/pixel). Three of the runs (with two blocks each) contained 195 images and the other (with three blocks) contained 285 images. Motion was corrected in real time during functional runs with prospective acquisition correction (PACE).
High-resolution structural images were also acquired for each participant using a T1-weighted 3D MP-RAGE sequence that was coplanar with the functional images (TR = 2500 ms; TE = 4.38 ms; flip angle = 8°, matrix size = 256 x 192; 160 contiguous axial slices; voxel size = 1 mm³; slice thickness = 1 mm; bandwidth = 130 Hz/pixel). Additionally, field map scans were acquired for each participant to correct for field inhomogeneities (TR = 500 ms; TE = 4.99 ms; flip angle = 55°; matrix size = 64 x 64; field of view = 200 mm; 32 axial slices with interleaved acquisition; slice thickness = 4 mm, bandwidth = 1530 Hz/pixel).

Diffusion Tensor Imaging (DTI) was performed at the Cape Universities Brain Imaging Centre (CUBIC), Tygerberg Hospital using a 3 T Siemens Allegra MRI scanner. Images were captured with a single-channel transmit-receive head coil in axial orientation with diffusion weighted parameters: TE = 88 ms, TR = 8800 ms, FOV = 22 cm, 65 slices, 1.8 × 1.8 × 2.0 mm³ spatial resolution, 0% distance factor and two-fold GRAPPA acceleration. Gradients were applied in 30 directions with b = 1000 mm/s² and 3 directions with b = 0 mm/s². The 5-min sequence was repeated 3 times per child, and acquisitions with poor image quality were excluded. All scans were clinically reported and children were referred on to the appropriate services if indicated.

Scanning was performed using a 3T Siemens (Erlangen, Germany) Allegra MRI scanner at the UCLA Ahmanson-Lovelace Brain Mapping Center. Functional images were acquired using T2^*-weighted EPI [slice thickness: 4 mm; 30 slices; TR (repetition time) = 2 s; TE (echo time) = 30 ms; FA (flip angle) = 90°; matrix size: 64 × 64; FOV (field of view) = 200 mm]. Each functional run consisted of 205 functional volumes. For registration, a T2-weighted matched-bandwidth high-resolution anatomical scan (same slice prescription as EPI, but higher in-plane resolution) was acquired in both of the two sessions. Additionally, a magnetization-prepared rapid-acquisition gradient echo (MPRAGE) image was acquired for each participant in the first session (TR = 2.3; TE = 2.1; FOV = 256 mm; matrix size: 192 × 192; saggital plane; slice thickness = 1 mm; 160 slices).

All patients underwent an imaging session in a 3 T Siemens Allegra MRI Scanner (Siemens, Erlangen, Germany) for a high-resolution T1 structural scan, and a resting-state functional scan. Whole-brain structural and functional (resting-state) imaging data was acquired using the following parameters: acquisition parameters for high-resolution T1-weighted images were as follows: echo time/repetition time (TE/TR) = 2.85/2200 ms, inversion time = 750 ms, field of view (FOV) = 256 mm, slice thickness = 1 mm, 176 slices, 256 × 240 acquisition matrix, voxel size = 1 mm³. Functional resting-state scans were acquired with eyes closed and an echo-planar sequence with the following parameters: TE/TR: 28/2000 ms, flip angle = 77°, scan duration = 10 min, FOV = 220 mm, slices = 300, slice thickness = 4.0 mm, and slices were obtained with whole brain coverage.