Table 1.
Sequence parameters for 4D and dynamic 2D VEPCASL angiography. Where only one value is stated this is applicable to both acquisition strategies
| Sequence parameter | Value (4D mode | dynamic 2D mode) |
|---|---|
| VEPCASL pulse train duration | 1000 ms |
| Number of vessel encodings | 8 |
| Number of linearly increasing pre‐pulses (N p) | 20 |
| Imaging plane | transverse slab | any orientation |
| In‐plane field of view | 220 × ~177 mm2 (subject dependent) |
| Slab thickness | 64 mm | 64–100 mm (orientation dependent) |
| Slice oversampling | 12.5% | – |
| In‐plane parallel acceleration | GRAPPA factor 2 |
| Voxel size | 1.2 × 1.0 × 4.0 mm3 | 1.2 × 1.0 × (64–100) mm3 |
| Reconstructed voxel sizea | 1.0 × 1.0 × 2.0 mm3 | 1.0 × 1.0 × (64–100) mm3 |
| Readout partial Fourier | 78% |
| Phase partial Fourier | 75% |
| Slice partial Fourier | 75% | – |
| Readout bandwidth | 496 Hz per pixel |
| Repetition time (T R) | 4.2 ms |
| Excitations per readout block | 14 |
| Temporal resolution | 59 ms |
| Echo time (T E) | 1.8 ms |
| Excitation flip angle | 40° |
| Number of readout blocks | ~12 (cardiac cycle dependent) |
| Transmit coil | body |
| Receive coil | 12 channel head |
| Time between VEPCASL preparations | ~two cardiac cycles |
| Total imaging time | ~18 min | ~1.5 min |
a
Via zero‐padding in k‐space.