Table 2.
Scan parameters for TWIST, gated CEMRA, and bT1RESS.
| TWIST | Gated CEMRA | bT1RESS | |
|---|---|---|---|
| Acquired voxel size (mm) | 2.29 × 1.38 × 2.54 | 1.35 × 1.15 × 2.92 | 2.19 × 2.19 × 2.20 |
| Reconstructed voxel size (mm) | 1.38 × 1.38 × 1.80 | 1.15 × 1.15 × 1.80 | 1.09 × 1.09 × 1.10 |
| Slice oversampling (%) | 0 | 8.3 | 50 |
| Field of view (mm) | 420 | 450 | 385 |
| # slices (acquired/reconstructed) | 56 | 48 | 64 |
| Partial Fourier (phase, slice) | 6/8, 6/8 | 7/8, 6/8 | 7/8, 7/8 |
| Asymmetric echo | Yes | Yes | No |
| Parallel acceleration | GRAPPA 2 | GRAPPA 2 | GRAPPA 2 × 2 |
| TR/TE/TI (ms) | 2.40/0.85/none | 2.75/0.94/none | 2.90/1.45/320 |
| Excitation flip angle (deg) | 25 | 40 | 70 |
| Magnetization preparation | No | No | Composite saturation, fat suppression |
| Electrocardiographic gating | No | Yes | Yes |
| Shot duration (ms) | n/a | 286 | 186 |
| Trigger delay (ms) | n/a | 250 | 300 |
| Bandwidth (Hz/pixel) | 650 | 590 | 1495 |
| Readout | 3D spoiled gradient-echo | 3D spoiled gradient-echo |
3D bSSFP |
| Image subtraction | Yes | No | No |
| Other | Central region A 33%, sampling density B 50%, 25 measurements | Contrast agent timing obtained using prior TWIST or fluoro triggering | Local shimming to heart and aorta |
TWIST time-resolved angiography with interleaved stochastic trajectories, CEMRA contrast-enhanced magnetic resonance angiography, bT1RESS balanced T1 relaxation-enhanced steady-state, GRAPPA generalized autocalibrating partially parallel acquisition, 3D three-dimensional, bSSFP balanced steady-state free precession, TR repetition time, TE echo time, TI time interval.