Hello,
without motion parameters, would it be sufficient for "unwarp" to use the default values "first order effects" = "4 5" = pitch and roll?
In my experience with a head-only scanner subjects tend to move out of the scanner a little. Voxels might become less sensitive/more distorted when being farther away from the center of the bore. Dunno, but would "unwarp" correct for this effect?
Best,
Gabor
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