Table 2.
Imaging parameters
| Sequence | T1wHealthy volunteer | Patient | dMRI | ||
|---|---|---|---|---|---|
| 1) B1000 | 2) B2000 | 3) Rev. enc | |||
| Field of view (mm) | 351 × 251x160 | 230 × 185x160 | 240 × 240x150 | 240 × 240x150 | 240 × 240x150 |
| Acquired voxel size (mm) | 1.2 × 1.2x1.2 | 1.25 × 1.25x1.25 | 2.5 × 2.5x2.5 | 2.5 × 2.5x2.5 | 2.5 × 2.5x2.5 |
| Echo time (ms) | 2.1 | 3.0 | 99 | 99 | 99 |
| Repetition time (ms) | 4.7 | 6.5 | 7000—8200 | 7000—8200 | 7000—8200 |
| [G, δ, Δ] [(mT/m), (ms), (ms)] | – | – | [15.9,38.9, 49.5] | [22.5, 38.9, 49.5] | [15.9, 38.9, 49.5] |
| Acceleration | CS 1.8 | CS 1.2 | S 1.8 | S 1.8 | S 1.8 |
| Acquisition time | 3 min. 52 | 3 min | 5 min | 1 min | |
| Diffusion encoding (s/mm2) | NA | NA |
1 × b = 0, 20 × b = 1000 |
5 × b = 0, 32 × b = 2000 |
1 × b = 0, 6 × b = 1000 |
| Phase encoding direction | RL | RL | AP | AP | PA |
| Imaging mode | 3D multishot TFE | MPRAGE | 2D Single shot EPI | 2D Single shot EPI EPI | 2D Single shot EPI |
The T1-weighted (T1w) acquisition of the healthy volunteers was based on the original clinical protocol. For the intraoperative acquisition of the patients, we aimed to increase the gray-white matter contrast of the T1w image and therefore used an MPRAGE acquisition. The first diffusion MRI (dMRI) acquisition is separated to send through to the clinical PACS system. The second acquisition completes the multi-shell dMRI dataset. The third acquisition is acquired only in patients, with reverse phase encoding (rev. enc.) direction settings to correct for the echo planar imaging (EPI) distortions. G = gradient amplitude, δ = gradient duration,Δ = temporal separation, S = SENSE, CS = compressed SENSE, AP = anterior–posterior, PA = posterior-anterior. TFE = turbo field echo, MPRAGE = magnetization prepared rapid gradient echoImaging