Hi Chris,
I think I see what's going on (so you don't need to upload your data;-))
Your bvals file does not contain a "0" where it should (whilst your
bvecs file does).
This is not a problem in dtifit since bvals and bvecs are multiplied
together.
It is a problem, however, for bedpostx, where the signal equation is
written in a way that does not involve multiplying bvecs and bvals
(for computational purposes).
So in your case, you need to replace the first element of your bvals
file by zero, and all should be fine.
Saad.
On 3 Nov 2008, at 20:07, SUBSCRIBE FSL Chris Ward wrote:
> After running BedpostX I looked at dyads modulated by FA (from
> DTIfit) and
> the resulting image has a lot more red and blue than normal. There
> is a
> limited amount of green, only at the core of where it is normally. The
> colour orientations are correct (red left-right, blue superior-
> inferior,
> green anterior-posterior). The RGB that I get from DTIfit from the
> same data
> appears normal (plenty of green).
>
> I can upload images if this would help, I am wondering if anyone has
> any
> ideas to what might be the problem.
>
> Thanks.
>
Saad Jbabdi
Oxford University FMRIB Centre
JR Hospital, Headington, OX3 9DU, UK
+44 (0) 1865 222545 (fax 717)
www.fmrib.ox.ac.uk/~saad
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