Hi,
On 12 May 2009, at 09:17, Chun Meng wrote:
> Dear FSL experts,
>
> We have questions about registrating FA of boys' brain ( age: 11~15)
> to standard space in TBSS analysis. Is there other good methods
> besides " tbss_2_reg -n" or finding proper pediatric brain template
> of FA?
This age range _may_ be close enough to adult brains to use the
FMRIB58_FA template - but I would probably try the -n option as well
and compare results, just to be safe.
> In detail, due to adult-derived FMRIB58_FA is inappropriate for
> children, as FSL website suggests, we used inter-subject alignment
> firstly and got a most-representative target image from about 30
> subjects. However more subjects add in today. It will cost much time
> to re-run "tbss_2_reg -n".
Doing -n on a reasonable subset of subjects is often acceptable, yes.
> Could I align all FA images with the former target image and then
> average them to get a new target image just like what FSL vbm did?
> In general, to get study-specific template, why TBSS don't use
> FSLvbm-style pipeline for mean_FA as we did for template_GM? If we
> want to combine results from VBM and TBSS analysis (i.e. Douaud,
> et.al., Brain, 2007), how to ensure the final alignment of FA images
> and GM images during registration or post analysis?
Yes, that should be ok. Once you've identified the target that you
were originally happy with you can use the -t option in tbss_2_reg to
rerun reg with a new set of input subjects.
The final space is MNI152 for both TBSS and FSLVBM - though at
different resolutions (1mm and 2mm respectively) - you can just
resample one set to combine them.
> By the way, is the mean of unfliped and fliped templates helpful for
> unbiased registration of FA images?
We didn't think this was helpful or necessary (in general) for the FA
WM analyses in TBSS, no.
Cheers.
>
> I am sorry to bother experts about such easy question. When I
> searched over old archives and found related issue: https://www.jiscmail.ac.uk/cgi-bin/webadmin?A2=ind0809&L=FSL&P=R59769
> But it seems no FA template for children of east Asia.
>
> Thanks a lot!
>
> Best regards!
>
> --
> Chun Meng, Master candidate
> NeuroImage Computing group,
> National key Laboratory of Cognitive Neuroscience and Learning,
> http://psychbrain.bnu.edu.cn/en/index.htm,
> Beijing Normal University,
> Beijing 100875, China
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Stephen M. Smith, Professor of Biomedical Engineering
Associate Director, Oxford University FMRIB Centre
FMRIB, JR Hospital, Headington, Oxford OX3 9DU, UK
+44 (0) 1865 222726 (fax 222717)
[log in to unmask] http://www.fmrib.ox.ac.uk/~steve
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