Hello,
I was wondering if there is a way to compute the halfway warps for data
that have been aligned using FNIRT, in a way that is similar to what is
done in SIENA with the FLIRT xfm matrices? The reason I ask is because I
have DTI data from two different systems on the same individual. The phase
encode is different across systems (A->P vs. P->A) and even with the field
map correction, I still observe differences in the geometric distortion
between the two scans. My thought was to use FNIRT to align the two
images (FA maps, for example) to remove any additional differences in
distortion and to use the halfway method to control for interpolation bias.
Any feedback is much appreciated!
-Ryan
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