MR Sites Fig.
1 shows an overview of the included MR sites.
Not all sites have provided the required information (scanner type,
serial number,
software version) for participation in the study.
Sequences Highly similar 3D-T2,
3D-FLAIR and 3D-T1 images were obtained,
see fig 2,
but adjustments of stock sequences were needed.
T1 MP-RAGE (Philips-Siemens) and IR-SGPR (GE) were accelerated with a factor two.
FLAIR,
SWI,
DTI and rs-fMRI required most adjustments.
To obtain visually similar contrast,
FLAIR inversion time is 1650ms on Philips Achieva,
2100ms on Siemens Trio,
1650ms on Skyra and 2152ms on GE 750W.
SWI was implemented successfully on GE,
Philips and Siemens based on [3].
Due to unavailability of SWI at participating Philips sites,
SWI was replaced with 3-D T2*.
It was not possible to fully standardize DTI due to limitations in the number of directions that are available on participating systems (Siemens max 30 or 64,
Philips max 32 and GE max 64),
and secondly because of sequence implementation and hardware (gradient) differences.
DTI TR/TE=9900/92ms on Siemens Trio,
11600/91ms on Skyra,
10062/97ms on Philips Achieva,
15550/74ms on GE 750W.
For rs-fMRI,
we could not achieve the same coverage on all scanners in a TR=2500ms (41 slices at Siemens Trio,
41 on Skyra,
45 on Philips Achieva,
32 on GE 750W).
Siemens and Philips B1 correction was applied on all sequences except SWI.
On GE,
B1 adjustment (“PURE”) is not available at selected sites.
Total scan time for this protocol on Siemens Trio is 40:05,
Philips Achieva 47:10 and GE 750W 46:48.
In figure 3 an example of a patient scan is shown.