We're attempting to process some FA images through TBSS and are encountering strange issues with some subjects. There's no obvious differences between subjects who go through the stream fine, and those that have problems. For the subjects that have problems, we get warnings similar to the following during the FNIRT step in tbss_2_reg:
Warning, Jacobian not within prescribed range. Prescription is 0.01 -- 100 and obtained range is -21.7124 -- 132.714
Warning, Jacobian not within prescribed range. Prescription is 0.01 -- 100 and obtained range is -8.85493 -- 66.6432
Warning, Jacobian not within prescribed range. Prescription is 0.01 -- 100 and obtained range is -13.4562 -- 209.94
And the images are horribly distorted after the warp.
I've looked at some past messages on the list with similar errors but haven't been able to find a solution for when the numbers are so far out of range.
Oddly though, if I first apply the FLIRT affine transformation to the image, and then process the transformed image with the same FNIRT command that TBSS uses, the results appear fine. Is it possible that the FNIRT step is not actually applying the FLIRT transform first?
--
Mike Angstadt
Research Computer Specialist / PANLab Lab Manager
Department of Psychiatry / University of Michigan
(734) 936-8229
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