Magnetom skyra mr scanner

All of the patients underwent preoperative rectal MRI on a 3T Magnetom Skyra MR scanner (Siemens Healthineers, Malvern, PA, USA) with a phased-array 18-channel body coil in the supine position. MRI protocols did not change during the 41-month study. Two rectal suppository pills were inserted to remove feces at 1 hour before MRI, and 10 mg of racanisodamine hydrochloride was injected intravenously to reduce rectal motility (unless contraindicated) at 30 min before MRI. High-resolution rectal MRI protocol comprised turbo spin echo sagittal, oblique coronal (angulated parallel to the long axis of the rectal tumor), and oblique axial (angulated perpendicular to the long axis of the rectal tumor) T2- and diffusion-weighted imaging using readout-segmented echo-planar imaging of long variable echo trains. The scan parameters used for the oblique axial T2-weighted imaging sequence were as follows: repetition time/echo time, 6,890/100; slice thickness, 3 mm; voxel size, 0.3×0.3×3 mm; field of view, 180 mm; matrix, 384×346; slices, 48; average, 3; total scanning time, 5 min and 5 s; and parallel acquisition technique with generalized auto-calibrating partial parallel acquisition acceleration factor, 2. Fat saturation techniques were not required.

All MR imaging were performed at a 3T Magnetom Skyra MR scanner (Siemens Healthcare). A standard T2-weighted imaging (T2WI) was required by turbo spin-echo in sagittal, oblique coronal (parallel to the rectum) planes, and oblique axial (perpendicular to the rectum)13 (link),(Supplementary Figure 1). The oblique axial acquisition was performed using the following parameters: Repetition time (TR)/echo time (TE), 6890/100; Field of view (FOV), 236×260 mm; matrix, 313 × 384; and slice thickness= 3 mm. We used the multishot echo planar imaging (EPI) performed with a reduced TE and encoding time for DWI (Supplementary Figure 2). TR/TE, 5500/61; slice thickness= 4.5 mm; slice gap= 0.5 mm; FOV, 216×216 mm; matrix, 128 × 128; b values of 0, 600, and 1000 s/mm2; echo spacing= 0.4 ms; number of readout segments= 3. The ADC map was automatically generated during image reconstruction (DWI: b values of 0 and 1000 s/mm2) (Supplementary Figure 3).