Table 3.
Detailed sequence parameters of compositional MRI sequences
| Imaging parameter | WASSR | gagCEST | T1 map | T2 map |
|---|---|---|---|---|
| FOV (mm) | 160 × 160 | 160 × 160 | 160 × 160 | 160 × 160 |
| Slice thickness (mm) | 5 | 5 | 7 | 3 mm |
| TE (ms) | 3.5 | 3.5 | 11 | 13.8/27.6, 41.4/55.2/69 |
| TR (ms) | 7.2 | 7.2 | 6000 | 1000 |
| TI (ms) | 25/50/100/500/1000/2000 | |||
| Resolution (mm/pixel) | 0.6 × 0.6 | 0.6 × 0.6 | 0.6 × 0.6 | 0.4 × 0.4 |
| Flip angle (°) | 15 | 15 | 180 | 180 |
| Pulsed CEST saturation module | ||||
| Frequency range (ppm – ppm) | − 1 to 1 | − 3 to 3 | ||
| Number of Dynamic Scans | 21 + 1 | 25 + 1 reference image | ||
| Number of saturation pulses | 1 | 8 | ||
| Pulse Duration tp (ms) | 54 | 300 (100, 200) | ||
| Interpulse Duration (ms) | – | 300 | ||
| B1 amplitude (µT) | 0.2 | 0.8 (0.6, 1.0) |
In healthy volunteers, pulse duration tp and B1 amplitude were evaluated at 100, 200, and 300 ms and at 0.6, 0.8, and 1.0 µT, respectively, while in patients, the following parameter settings were used: 300 ms and 0.8 µT
WASSR water saturation, gagCEST glycosaminoglycan chemical exchange saturation transfer imaging, FOV field of view, TE echo time, TR repetition time, TI inversion time