Sense body coil

Cardiac MRI was performed at 1.5 T (Intera, Philips, Amsterdam, the Netherlands) in all animals using a four-channel phased array surface coil (SENSE Body Coil, Philips). A breath-held, ECG-gated cine steady-state precession MRI was acquired (TR/TE 4.1/2.1 ms; flip angle 60°; field of view 320 × 320 mm; matrix 160 × 160 pixels, slice thickness 7 mm; bandwidth 1249.7 Hz/pixel). Delayed enhancement images were acquired after intravenous gadolinium (Gd-DTPA, 0.2 mL/kg) using a phase-sensitive inversion recovery sequence (TR/TE 4.9/1.6 ms; flip angle 15°; inversion time 157 ms; field of view 330 × 330 mm; matrix 224 × 200 pixels; slice thickness 10 mm, bandwidth 282.3 Hz/pixel). The left ventricular ejection fraction (LVEF), left ventricular end-systolic volume (LVESV), and left ventricular end-diastolic volume (LVEDV) were measured at baseline, 48 h after MI, and before sacrifice. Independent blinded investigators carried out the MRI data acquisition and analysis.

All subjects underwent two MRI examinations with a 1.5-T MR scanner (Achieva, Philips Medical Systems, Best, The Netherlands) using a phased array body coil (SENSE body coil, Philips Medical Systems, Best, The Netherlands). Examinations were performed before the initiation of treatment and at the 5^th fraction radiotherapy (RT) point. All MRI examinations contained axial spin-echo T1 weighted imaging (TR/TE 423/100 ms, average number 1, FOV 365×284mm, matrix 320, slice thickness 4 mm, skip 1.2–1.6 mm and slice 20), axial turbo spin-echo T2 weighted imaging (TR/TE 2,000/70 ms, flip angle 180°, concatenations 2, average number 2, FOV 300×280 mm, matrix 288, slice thickness 4 mm, skip 1.2–1.6 mm and slice 20), T1 with contrast enhanced imaging including sagittal and transverse axial, and then DWI (TR/TE/TI 10,205/70/180 ms, FOV 450×366mm, matrix 256, slice thickness/gap 4/0 mm, slice 20, EPI factor (echo train length) 43). DWI scans were obtained using a single-shot spin-echo type of echo-planar sequence, and fat signals were suppressed using short-tau inversion recovery (STIR). The DWI b-values were b=0 and 1,000s/mm². An interval of 7 min was allocated to acquire DWI with free breathing.

Cardiac MRI was performed at 1.5 T (Intera; Philips, Amsterdam, The Netherlands, http://www.usa.philips.com) in all animals by using a four‐channel phased array surface coil (SENSE Body Coil, Philips). Breath‐held, ECG‐gated cine steady‐state precession MRI was acquired (TR/TE 4.1/2.1 ms; flip angle 60°; field of view [FOV] 320 × 320 mm; matrix 160 × 160 pixels; slice thickness 7 mm; bandwidth 1,249.7 Hz per pixel). Delayed enhancement images were acquired after intravenous gadolinium (0.2 ml/kg) using a phase‐sensitive inversion recovery sequence (TR/TE 4.9/1.6 ms; flip angle 15°; inversion time 157 ms; FOV 330 × 330 mm; matrix 224 × 200 pixels; slice thickness 10 mm; bandwidth 282.3 Hz per pixel). Left ventricular ejection fraction (LVEF), cardiac output (CO), stroke volume (SV), left ventricular end‐systolic volume (LVESV), left ventricular end‐diastolic volume (LVEDV), and left ventricular end‐diastolic wall mass (LVEDWM) were measured at baseline, 48 hours after MI, and before sacrifice. Independent blinded investigators carried out MRI data acquisition and analysis.

All MRI scans were performed on a 3T MRI unit (GE DISCOVERY MR750, China-Japan Friendship Hospital) with a surface coil wrapped around the hips (SENSE Body Coil, Philips Healthcare, The Netherlands). The patients were imaged in a supine position, with the hips positioned neutrally and legs straight. Imaging sequences included fat-saturated proton-density weighted imaging (PD-FS), three-dimension double echo steady-state sequence (3D-DESS), and quantitative Cube T2 -mapping. The MRI parameters were optimized to achieve the highest signal noise ratio (SNR) and image quality. T2-mapping was conducted using similar imaging parameters to enable comparison. The repetition time (TR) was 1000 ms, while the echo time (TE) was set to 32 ms. The slice thickness was chosen to be 3.5 mm with a spacing of 0.7 mm. The field of view (FOV) was 256 mm × 256 mm. And the number of excitations (NEX) was set to 1. Each participant was required to rest for 30 minutes before the knee scan to ensure that the cartilage was resting.
We used an advanced cartilage analysis application (IntelliSpace Portal, Philips Healthcare) to analyze the reconstructed T2 maps. Local T2 values can be determined through T2 mapping using multiecho (ME) SE methods [29 (link)].