Dstream torso coil

For MR imaging, a standard spine protocol was used including a sagittal T1-weighted sequence with turbo spin echo (T1w TSE) and a sagittal STIR sequence. To measure the signal of tissues with short T₂* values, a 3D UTE stack-of-stars sequence was employed [23 (link), 24 (link)] with a non-selective rectangular RF pulse. The RF excitation was followed by a variable-duration slice encoding gradient. The following scan parameters were used: echo time 0.14 ms, repetition time 6.3 ms, flip angle 5°, field of view (FOV) 250 × 250 × 279 mm³, voxel size (acquired) 0.45 × 0.45 × 3 mm³, voxel size (reconstructed) 0.28 × 0.28 × 0.75 mm³ and acquisition time 6.3 ± 0.23 min, ramp length 0.08 ms, max. gradient strength 15.04 mT/m, sampling dwell time 3.12 μs with 568 samples, acquisition window 1.77 ms, 945 number of spokes, with radial percentage of 85%, partial Fourier with a factor of 0.6 in slice direction. Image reconstruction was performed offline and gradient imperfections were corrected by means of a gradient impulse response function [23 (link)]. During the reconstruction, the images were Fourier interpolated from the acquired resolution to the reconstruction resolution. All participants were examined using a 3-Tesla MR scanner (Ingenia; Philips Healthcare) with dedicated 16-channel anterior and posterior body coils (dStream Torso coil, Philips Healthcare).

All subjects underwent MRI at 3 Tesla (Ingenia, Philips Healthcare, Best, Netherlands) using the built-in 12-channel posterior coil and a 16-channel anterior coil (dStream Torso coil, Philips Healthcare, Best, Netherlands). Subjects were positioned head-first in supine position.
The imaging protocol comprised an axially prescribed, six-echo three-dimensional (3D) spoiled gradient echo sequence in two stacks for chemical shift encoding-based water–fat separation at the cervical and lumbar spine, respectively.
The dedicated sequence parameters were set as follows: field of view (FOV) = 400 × 300 × 140 mm³ (RL × AP × FH), acquisition matrix size = 268 × 201 × 93 mm³, acquisition voxel size = 1.5 × 1.5 × 1.5 mm³, SENSE with reduction factor = 2.5 × 1.0 mm³ (AP × FH, phase × slice). The six echoes were acquired in a single TR using non-flyback (bipolar) read-out gradients; cervical stack: repetition time (TR)/echo time (TE_min)/echo time step (ΔTE) = 8.2/1.24/1.0 ms, number of signal averages (NSA) = 3, resulting scan time = 4:16 min; lumbar stack: TR/TE_min/ΔTE = 12.0/1.24/1.0 ms, NSA = 2, resulting scan time = 2:01 min.

The Ingenia 3.0T CX and dStream Torso Coil, which were MRI equipment from Philips (Royal Philips Electronics N. V, Netherlands), were used for data collection. RT was used to proceed with the test according to the patient’s breathing. When the RT-2D-SENSE TSE Pulse Sequence technique was applied, the reduction factor was set to 1 and the patient was tested while breathing through the RT function. In the RT-2D-CS TSE technique to which the Compressed SENSE technique was applied, 1.3 was set as the standard external reduction factor among five factors (1.1, 1.2, 1.3, 1.4, and 1.5), where 1.3 was a value that could maintain the optimal SNR while reducing the image acquisition time. The denoising level was set to Medium among values of No, Weak, Medium, and Strong. The BH-2D SSTSE technique was performed using the breath-hold technique eleven times, and images were acquired while patients were holding their breath for 12 s each.

All patients underwent MRI examinations pre-dCRT (within five days before dCRT) and post-dCRT (2–3 weeks after the start of dCRT) on a 3.0T MR scanner (Ingenia 3.0 T; Philips Medical Systems, Best, the Netherlands), with a 32-channel dStream Torso coil. Patients were trained in breath-holding before MRI examination and instructed to avoid swallowing during the scan.
Axial BOLD MR images were obtained using the respiratory-triggered multiple fast field echo (mFFE) sequence. The scan parameters were as follows: repetition time (TR), 100 ms; range of echo time (TE), 4–40 ms; flip angle, 27°; slice thickness, 5 mm; interslice gap, 1.5 mm. field of view (FOV), 400 × 400 mm; slices, 12. The corresponding T2* mappings were automatically generated. Axial T2-weighted (T2W) images were collected as high-resolution structural maps using a respiratory-triggered turbo spin-echo sequence (TR, 1000 msec; TE, 80 msec; matrix, 260 × 228; section thickness, 5 mm; gap, 0.5 mm; field of view (FOV), 390 × 390 mm; slices, 32).