Discrete lesions identified on diffusion-weighted MR imaging (DWI) and high-resolution DWI (DWI-HR)
| DWI | DWI-HR | P Value | |
|---|---|---|---|
| Signal-to-noise ratio, mean (range) | 29.7 (23.9–37) | 35.6 (27.7–43.2) | <.01 |
| Contrast-to-noise ratio, mean (range) | 10.7 (8–17) | 14.8 (12.6–20.6) | <.01 |
| Total no. of lesions | 129 | 253 | <.001 |
| Average no. of lesions | 3.07 | 6.04 | <.001 |
| No. of unique lesions | 7 | 123 | <.001 |
| Total lesion volume (mm3) | 7040 ± 2010 | 7052 ± 1950 | .95 |
| Average volume per lesion (mm3) | 3600 ± 1300 | 2800 ± 1200 | <.001 |
| Average volume per lesion of unique lesions (mm3) | 134.41 ± 88.23 | 70.50 ± 16.90 | .65 |
| No. of patients with a single lesions, n (%) | 16 (37%) | 12 (28%) | n/a |
| Number of patients with greater than 5 lesions, n (%) | 8 (19%) | 19 (42%) | n/a |
Note:—DWI-HR was acquired following a tetrahedronal encoding scheme with the following gradient directions: (0, 1, 1), (−1, 0, 1), (0, 1, 1), (1, 1, 0), (0, 1, −1), (−1, 1, 0). 100% gradient strength was applied simultaneously along 2 axes affecting a factor of 2 gain in ‖b‖, and allowing for a shorter echo time.