Table 1.
Suggested sequences for DWIBS at 1.5 T (++ very good, + good, +/− moderate, − poor, −− very poor; FOV field of view, RFOV rectangular FOV, NA not applicable, TE echo time, TI inversion time, TR repetition time)
| Name | DWIBS-STIR | DWIBS-CHESS |
|---|---|---|
| Main characteristics | Most suitable for organs and body regions suffering from large magnetic field inhomogeneities | Most suitable for organs and body regions without significant magnetic field inhomogeneities |
| Useful in suppressing bowel signal | Relatively higher SNR than DWIBS-STIR | |
| Relatively lower SNR than DWIBS-CHESS | Relatively less time-consuming than DWIBS-STIR | |
| Relatively more time-consuming than DWIBS-CHESS | ||
| Suitability | ||
| Neck and shoulder | ++ | − |
| Chest | ++ | + |
| Abdomen and pelvis | ||
| Liver, pancreas, spleen | + | ++ |
| Colon | ++ | + |
| Kidneys | ++ | + |
| Uterus, bladder | + | ++ |
| Prostate | + | + |
| Extremities | ++ | + |
| Imaging parameters | ||
| Fat suppression | STIR | CHESS |
| b-value (s/mm2) | 1,000a, b | 1,000a, b |
| Direction of MPGs | Phase, frequency, and slice | Phase, frequency, and slice |
| TR (ms) | 10,205 | 7,800 |
| TE (ms) | 70 | 70 |
| TI (ms) | 180 | NA |
| Parallel imaging factor | 2 | 2 |
| Halfscan factor | 0.6 | 0.6 |
| EPI factor | 47 | 47 |
| Slice orientation | Axial | Axial |
| No. of slices | 60 | 60 |
| Slice thickness/gap (mm) | 4/0 | 4/0 |
| FOV (mm) | 400 | 400 |
| RFOV (%) | 70 | 70 |
| Matrix | 160 | 160 |
| Scan percentage | 70% | 70% |
| Actual voxel size (mm3) | 2.5 × 3.6 × 4.0 | 2.5 × 3.6 × 4.0 |
| Calculated voxel size (mm3) | 1.6 × 1.6 × 4.0 | 1.6 × 1.6 × 4.0 |
| No. of signals averaged | 10 | 6 |
| Scan time | 7 min 8 s | 3 min 2 s |
aFor imaging of the upper abdomen (including liver, spleen, and pancreas), a b-value of 500 s/mm2 can be applied, if necessary combined with respiratory triggered scanning
bFor tumor detection in the prostate, b-values in the order of 1,500–2,000 s/mm2 can be applied