Hi Sushravya,
by no mean a flirt (or any affine) registration would be enough to match the WM across the subjects, especially if you're dealing with healthy elderly and MCI patients!
What you might have found in the archives is that flirt is working better than areg (present in an old version of TBSS) for placing the best target into the MNI space... This is obsolete now (we only use flirt and fnirt) and is not valid if you have used the tbss2 -T recommended option anyway.
What are the commands/option you're run exactly for tbss2 and 3? Could you please maybe upload (http://www.fmrib.ox.ac.uk/cgi-bin/upload.cgi) an example of one FA_to_target that has failed?
Cheers,
Gwenaelle
--- En date de : Mar 26.5.09, Sushravya Raghunath <[log in to unmask]> a écrit :
> De: Sushravya Raghunath <[log in to unmask]>
> Objet: [FSL] registered images distorted - tbss_3_postreg step
> À: [log in to unmask]
> Date: Mardi 26 Mai 2009, 19h34
> Experts,
>
> I am running TBSS Analysis of Control versus MCI human
> subjects.
>
> The _FA_to_target.nii.gz images (resulting after
> tbss_3_postreg step) are
> distorted. In some cases the regsitered images have
> truncated edges whereas
> FA image is complete.
>
> I read in older posts that FLIRT registration might be
> better and registered the
> FA image to MNI152_T1_1mm_brain usifn FLIRT. The FLIRT
> registered images
> look better. The truncated edges are still seen with FLIRT
> registration but they
> are better than tbss registered images.
>
> Is this the right way of going about in such situation?
>
> If yes, how can I have FLIRT registration done in
> tbss_3_postreg step?
>
> Any suggestion would be helpful.
>
> Thanks,
> Sushravya
>
|