Ge 3t signa hdx mr scanner

All MRI scans were acquired on a GE 3T Signa^® HDx MR scanner (GE Healthcare) with an 8-channel head coil. During each session, 180 T1-weighted 1-mm³ isotropic volumetric inversion recovery fast spoiled gradient-recalled images, with CSF suppressed, were obtained to cover the whole brain with the following parameters: time of echo = 3.8 ms, time of repetition of acquisition = 8.6 ms, time of inversion = 831 ms, repetition time of inversion = 2332 ms, flip angle = 8°, and receiver bandwidth = ±20.8 kHz.
After the T1 data acquisition, first and high-order shimming procedures were carried out to improve magnetic field homogeneity. The DTI data were acquired with a dual spin-echo echo-planar imaging sequence for 12 minutes and 6 seconds with the following parameters: 48 contiguous 2.4-mm axial slices in an interleaved order, field of view = 22 × 22 cm, matrix size = 128 × 128, number of excitations = 2, echo time = 77.5 ms, repetition time = 13.7 s, 25 diffusion-weighted volumes (one per gradient direction) with b = 1000 s/mm², one volume with b = 0 and parallel imaging acceleration factor = 2. One staff member sat inside the scanner room next to the child at all times to monitor the child’s comfort and to ensure cooperation during scanning. During acquisition of volumetric T1-weighted scans and DTI scans, the children viewed a movie to help them stay still.

During the rsfMRI scan, children lay supine with their eyes open. They were instructed to remain as still as possible. Preceding the MRI scanning session, all children were trained during a separate visit with a mock scanner to familiarize and desensitize them to the sights and sounds of the scanner and to practice being still inside the scanner bore (Chang & Zhu, 2015 (link); Chang et al., 2016 (link)). To ensure that the child remained calm and to minimize the possibility of movement, an experimenter sat by the child throughout the duration of the scan. All MRI scans were acquired on a GE 3T Signa HDx MR scanner (GE Healthcare) with an 8-channel head coil. During each session, 180 T1-weighted 1-mm³ isotropic volumetric inversion recovery fast spoiled gradient-recalled images (3D IRFSPGR) (10 min scan time), with CSF suppressed, were obtained to cover the whole brain with the following parameters: time of echo = 3.8 ms, time 2332 ms, flip angle = 8°, field of view = 25.6 cm × 25.6 cm, matrix size = 256 × 256, slice thickness = 1 mm, and receiver bandwidth = 20.8 kHz.