Hi - This happens when you don' have a carriage return at the end of your
bvals/bvecs files. Did you check that?
Saad.
> Dear List,
>
> I'm using FSL to process a DTI data set acquired with 6 gradient
> directions + 1 b0, 4 repetitions. I eddy-correct them by coregistering
> all other images to first b0 image and then use bet to create brain
> mask. A 4d data set is then created by concatinating all images using
> avwmerge. Up to this point, everything seems to be fine, as I check the
> mask and 4d data using fslview. However, when I run dtifit as my last
> step, it processes as normal but the output isn't right as FA image is
> uniformly zero. Does someone have any idea what might wrong? The
> following is my bvec and bval file contents. I appreciate any comment!
>
> bvec:
> 0.0000 0.7071 -0.7071 0.0000 0.0000 0.7071 -0.7071 0.0000 0.7071 -0.7071
> 0.0000 0.0000 0.7071 -0.7071 0.0000 0.7071 -0.7071 0.0000 0.0000 0.7071
> - 0.7071 0.0000 0.7071 -0.7071 0.0000 0.0000 0.7071 -0.7071
> 0.0000 0.0000 0.0000 -0.7071 -0.7071 -0.7071 -0.7071 0.0000 0.0000
> 0.0000 - 0.7071 -0.7071 -0.7071 -0.7071 0.0000 0.0000 0.0000 -0.7071
> -0.7071 -0.7071- 0.7071 0.0000 0.0000 0.0000 -0.7071 -0.7071 -0.7071
> -0.7071
> 0.0000 0.7071 0.7071 0.7071 -0.7071 0.0000 0.0000 0.0000 0.7071 0.7071
> 0.7071 -0.7071 0.0000 0.0000 0.0000 0.7071 0.7071 0.7071 -0.7071 0.0000
> 0.0000 0.0000 0.7071 0.7071 0.7071 -0.7071 0.0000 0.0000
> bval:
> 0 1000 1000 1000 1000 1000 1000 0 1000 1000 1000 1000 1000 1000 0 1000
> 1000 1000 1000 1000 1000 0 1000 1000 1000 1000 1000 1000
>
> Regards,
> Deqiang Qiu
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