Table 1.
MRI protocol
| Sequences | Description |
|---|---|
| Coronal and sagittal T2w fast SE sequences | Repetition time/echo time: 2500–5000 ms/100 ms |
| Matrix: 256 × 256 | |
| Echo train length: 16 | |
| Acquired signals: 4 | |
| FOV: 24 cm | |
| Slice thickness: 4 mm | |
| Intersection gap: 1 mm | |
| Oblique HR images | Repetition time/echo time: 2500–5000 ms/100 ms |
| Matrix: 256 × 256 | |
| Echo train length: 16 | |
| Acquired signals: 4 | |
| Plane: orthogonal to the tumour | |
| FOV: 18 cm | |
| Slice thickness: 3 mm | |
| No intersection gap | |
| Axial T2w fast SE sequences | Repetition time/echo time: 2500–5000 ms/100 ms |
| Matrix: 256 × 256 | |
| Echo train length: 16 | |
| Acquired signals: 4 | |
| FOV: 34–40 cm | |
| Slice thickness: 4 mm | |
| Intersection gap: 0.5 mm | |
| Axial DW images (b-values: 0 and 1000 s mm−2) | Single-shot/echoplanar imaging |
| Echo time/repetition time: minimum/>8000 ms | |
| Signal averages: 8 | |
| FOV: 34–40 cm | |
| Matrix: 128 × 128 | |
| Slice thickness: 4 mm | |
| Slice spacing: 0.5 mm |
DW, diffusion-weighted; FOV, field of view; HR, high-resolution; SE, spin-echo; T2w, T2 weighted.
Axial T2w images were obtained using the same parameters as those for axial DW images; our choice of the FOV was a compromise between voxel size, volume coverage and signal-to-noise ratio, with a maximum FOV of 40 cm. Smaller FOVs (34–40 cm) were also used, depending on the patient characteristics. The total imaging time was 25 min.