Table 1.
Method | Sequence type | TR/TE (ms) | Comments |
T1 | RARE | 5500, 3000, 1500, 1000, 385.8/9.66 | NA = 1; FOV = 30 mm × 30 mm; rare factor = 2, matrix size = 256 × 128 (reconstructed phase encoding steps = 128; acquisition phase encoding steps = 96); yielding spatial resolution of 0.117 × 0.234 mm/pixel. Approximately 9 min acquisition time. |
T2 | MSME, fat suppressed | 4000/twelve echoes equally spaced from 6.28 to 75.4 | NA = 1; FOV = 30 mm × 30 mm; matrix size = 256 × 128 (reconstructed phase encoding steps = 128; acquisition phase encoding steps = 91); spatial resolution of 0.117 × 0.234 mm/pixel. 10 contiguous slices were acquired with respiration gating to cover the entire abdomen. Approximately 6 min acquisition time. |
ADC | EPI | 2500/17.7 | Echo train length = 16; Pulse duration = 3.0 ms; Diffusion time = 7.46 ms; NA = 1; FOV = 30 × 30 mm2; matrix size = 128 × 128; spatial resolution of 0.234 × 0.234 mm/pixel; 8 b values (7, 47, 81, 126, 180, 234, 340, 549) s/mm2. 10 contiguous slices were acquired to cover the entire abdomen. Approximately 2 min 40 s acquisition time. |
CEST | (1) RARE | (1) 2200 / 7 | (1) Center frequency estimate: Continuous-wave block saturation pulse with B1 = 3 μT and duration = 1 s; 25 frequency offsets from -360 Hz to 360 Hz with an interval of 0.5 ppm (WASSR approach). FOV = 30 mm x 30 mm; Matrix size = 128 x 128; Flip angle = 180o; NA = 1. A single, 1 mm slice delineating the tumor was acquired. |
(2) RARE | (2) 5000 / 7 | (2) Frequency shift saturation: 14 frequency offsets at ± 0.5, ± 1.0. ± 1.5, ± 2.0, ± 2.5, ± 3.0, ± 3.5 ppm were acquired through the same single slice using respiration gating with an off-resonance radiofrequency pulse applied for 1 s at a power of 3 μT. Matrix = 128 × 128 (reconstructed phase encoding steps = 128; acquisition phase encoding steps = 96); FOV = 30 mm × 30 mm; rare factor = 8. | |
(3) RARE | (3) 5000 / 7 | (3) Control image: A control image was acquired through the same slice using the same settings as #2, except with saturation offset at 300 ppm. Approximately 30 min total acquisition time. | |
MTR | GRE | 625 / 2 | Flip angle = 30°; off-resonance frequency 7000 Hz; saturation pulse block pulse shape = 50 ms width and 10 µT amplitude; FOV = 30 mm × 30 mm; matrix size = 256 × 256; spatial resolution of 0.117 x 0.117 mm/pixel. 10 contiguous images were acquired to cover the entire abdomen. Approximately 3 min acquisition time. |
ADC: Apparent diffusion coefficient; CEST: Chemical exchange saturation transfer; MTR: Magnetization transfer ratio.