Magnetom trio 3t mr scanner

MRI scanning was conducted on a Siemens MAGNETOM Trio 3 T MR Scanner at the Henry H. Wheeler, Jr. Brain Imaging Center at the University of California, Berkeley. Anatomical images consisted of 160 slices acquired using a T1-weighted MP-RAGE protocol (TR = 2300 ms, TE = 2.98 ms, FOV = 256 mm, matrix size = 256 × 256, voxel size = 1 mm³). Functional images consisted of 24 slices acquired with a gradient echoplanar imaging protocol (TR = 1370 ms, TE = 27 ms, FOV = 225 mm, matrix size = 96 × 96, voxel size = 2.3 × 2.3 × 3.5 mm). A projector (Avotec SV-6011, http://www.avotecinc.com, Stuart, Florida) was used to display the image on a translucent screen placed within the scanner bore behind the head coil. A mirror was used to allow the subject to see the display. Subjects made their responses via an MRI-safe fiber optic response pad (Inline Model HH-1 × 4-L, http://www.crsltd.com, Rochester, Kent, UK).

Magnetic resonance imaging was performed using a Magnetom Trio 3T MR scanner (Siemens Healthcare, Erlangen, Germany) in all patients with brain metastases. For the 354 patients with GBM at the Tiantan Hospital, Magnetom Trio 3T MR scanner was used in the 253 patients. In the remaining 101 patients, MRI was performed using Sigma 3T MR scanner (General Electric Company). For T2-weighted images, the specifications were as follows: repetition time, 4,500–6,000 ms; echo time, 84–122.5 ms; slice thickness, 3–5 mm; field of view, (180–240) mm × (219–256) mm; and matrix size, (160–512) × (208--512) pixels. For CE images, enhancement was achieved by injecting gadolinium-diethylenetriamine penta-acetic acid (0.1 mmol/kg, Beijing Beilu Pharmaceutical, Beijing, China), and the acquisition parameters were as follows: repetition time, 560--2520 ms; echo time, 2.3--19.7 ms; and slice thickness, 3--5 mm. The MR images of GBMs from the TCGA database were downloaded from the Cancer Imaging Archive.¹Lesions were manually segmented on T2-weighted images (tumor and peritumoral edema area) and CE images (tumor area) by two neurosurgeons using MRIcro.² Segmentation was evaluated by a neuroradiologist with more than 20 years of experience in brain tumor diagnosis.

An anatomical 3D T1-weighted MP-RAGE sequence with matrix size = 256 × 256 × 192; voxel size = 1 × 1 × 1 mm; TR/TE/TI = 1550/3.04/800 ms; flip angle = 9° was acquired for all patients using a Siemens Magnetom Trio 3T MR scanner or a Siemens 3T Verio MR scanner. All single-subject MRI sequences were corrected for gradient nonlinearities according to Jovicich et al. (2006 (link)), in order to correct for spatial distortions and achieve optimal PET-MR co-registration. All of the acquired MR images were examined for structural abnormalities, as a criterion for subject inclusion.

Functional MRI data were acquired on a Magnetom Trio 3T MR Scanner (Siemens AG, Erlangen, Germany). During the resting-state fMRI session, the participants were instructed to relax with their eyes closed and keep their heads still during the scans. Functional images were subsequently acquired in the same slice orientation with a GRE-EPI (gradient recalled echo, echo-planar imaging) sequence (TR/TE = 2,000 ms/30 ms, FOV 24.0 × 24.0 cm², FA 90°, matrix 64 × 64, slice thickness 4.0 mm, slice gap 0.4 mm, 30 slices, acquisition voxel size = 3.0 × 3.0 × 3.0 mm) for eight minutes and twenty seconds (250 measurements). 3D T1-weighted images were also acquired by using a 3DMPRAGE sequence, matrix 256 × 256, slice thickness 1.0 mm.

All MRI scans were acquired using a Siemens MAGNETOM Trio 3T MR scanner at the Imaging Center for Brain Research at Beijing Normal University. Foam padding and a plastic brace were used to minimize head movement. For the functional imaging, the whole-brain coverage of 33 axial slices was acquired using a T2-weighted echo-planar imaging sequence based on the blood oxygenation level-dependent (BOLD) contrast with the following parameters: 2000 ms repetition time (TR), 30 ms echo time (TE), 90° flip angle, 4.0-mm slice thickness, 0.6-mm gap, 64 × 64 data matrix, 200-mm field of view (FOV), and 3.1 × 3.1 × 4.0-mm voxel size. In addition, 3D structural brain scans were also acquired for each participant using a T1-weighted anatomical scan with the following parameters: 2530-ms TR, 3.39-ms TE, 7° flip angle, 256 × 256 data matrix, 256-mm FOV, 1.3 × 1.0 × 1.3-mm voxel size, and Bandwidth (BW) = 190 Hz/pixel.