Hi Cherif,
Yes this will very likely be different because of interpolation
effects when inverting the nonlinear warp field. It is probably
_slightly_ more robust to use the first method, but either should be ok.
Cheers.
On 30 Oct 2008, at 01:20, Cherif Sahyoun wrote:
> Hi,
>
> I am interested in extracting mean FA values for my individual
> subjects in
> areas where I'm finding group differences using TBSS (for further
> analysis
> to know what's going on in those blobs).
> I drew an ROI on the skeleton over significant voxels and then tried
> 2 things:
> - fslmeants -i all_FA skeletonized -m myROI
> - and tbss_deproject myROI 2, followed by binarizing the outputs and
> using
> those as masks in fslstats -M on the corresponding native space FA
> maps.
> I found that although very similar, the values are off for a few
> subjects
> when I compare the 2 methods...
>
> Why would that be, and which set of values do you reckon I should use?
>
> Thanks,
> Cherif
>
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Stephen M. Smith, Professor of Biomedical Engineering
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FMRIB, JR Hospital, Headington, Oxford OX3 9DU, UK
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