MR imaging parameters |
TR = Repetition time; TE = echo time; TI = inversion time; FA = flip angle; ST = slice thickness; NEX = number of excitations; FOV = field of view, and VS = voxel size. |
3D T1-weighted sequence |
Stavanger University Hospital |
FFE, TR/TE/FA = 10.0 ms/4.6 ms/30°, ST = 2 mm with 1 mm spacing between slices, NEX = 2, Image Matrix = 256 × 256, FOV 26 cm, VS = 1.0156 × 1.0156 × 1 mm. |
Haugesund Hospital |
FFE, TR/TE/FA 20.0 ms/4.6 ms, 30°, ST = 1 mm with 1 mm spacing, NEX = 1, Image Matrix = 256 × 256, FOV 26 cm, VS = 0.5078 × 0.5078 × 1 mm. |
Haraldsplass Deaconess Hospital, Bergen |
FSPGR IR prepped, TR/TE/TI/FA 8.3 ms/3.2 ms/500 ms/7°, ST = 1 mm with 1 mm spacing, NEX = 1, Image Matrix = 256 × 256, FOV 25.6 cm, VS = 1 × 1 × 1 mm. |
Bergen (ParkWest) |
TR/TE/TI/FA 2,130.0/3.9 msec/1,100 msec/15°, ST = 1 mm with 1 mm spacing, NEX 1, Image Matrix 256 × 256, FOV 25 cm, VS = 0.9766 × 0.9766 × 1 mm. |
Arendal |
FFE, TR/TE/FA 25/6.9 msec/30°, ST = 2 mm with 2 mm spacing, NEX 1, Image Matrix 256 × 256, FOV 26.0 cm, VS = 1.0156 × 1.0156 × 2. |
FLAIR sequence |
Stavanger University Hospital |
TR/TE/TI/FA 6,000 ms/100 ms/2,000 ms/90°, ST = 4 mm with 5 mm spacing, NEX = 2, Image Matrix = 256 × 256, FOV 23.0 cm, VS = 0.8984 × 0.8984 × 4 mm. |
Haugesund Hospital |
TR/TE/TI/FA 6,000 ms/110 ms/2,000 ms/90°, ST = 4 mm with 5 mm spacing, NEX = 2, FOV 24.0 cm, Image Matrix = 512 × 512, VS = 0.4688 × 0.4688 × 4 mm. |
Haraldsplass deaconess hospital, Bergen |
TR/TE/TI/FA = 7,927 ms/105 ms/1,981 ms/90°, ST = 4 mm with 5 mm spacing, NEX = 1, Image Matrix 256 × 256, FOV 25.0 cm, VS = 0.9766 × 0.9766 × 4 mm. |
Bergen |
TR/TE/TI/FA 8,400/103/2,500/150, ST = 4 mm with 4.4 mm spacing, NEX 2, Image Matrix 256 × 204, VS = 0.9766 × 0.9766 × 4 mm. |
Arendal |
TR/TE/TI/FA 6,000/100/1,900/90°, ST = 4 mm with 5 mm spacing, NEX 2, Image Matrix 256 × 256, FOV 23.0 cm og VS = 0.8984 × 0.8984 × 4 mm. |
Scanner reliability analysis |
The human phantoms were scanned twice, 1 h apart, in all centers to analyze scanner reliability between centers. Scanning was organized with two separate sessions, 1 h apart, on the same day. From these scans, the total brain white matter was segmented from the T1 image and the volume calculated for the two MRI acquisitions at all four centers using FreeSurfer (http://surfer.nmr.mgh.harvard.edu/). |