Dear FSL experts
I have some DTI datasets that was acquired on a Siemens syngo
scanner sometime back. The data was acquired in the RAS format and
the bvecs for the scanner are prescribed in the LPS format. So, I
made the data into LAS format by using fslswapdim input -x y z
output; fslorient -swaporient output. I also multiplied the y
component of my original bvecs by -1 to make it correspond to LAS.
But, now my dtifit (V1) is wrong.
But, if I use a bvec that would correspond to LPI format ( by
multiplying the z component of the original bvecs with -1) with data
in LAS, I get correct dtifit. Is that possible? In one of the
previous postings, it was said that the bvectors relate to the image
co-ordinates. What exactly did that mean?
Also, I'm getting the exact same results as above (V1 and FA) when my
bvectors are in RAS and my data is in LAS. I'd assume that bvectors
and -bvectors should act the same for V1 calculations, is that right?
Thanks,
-Merry
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