Indeed - though because this is TBSS you'll need the 2D option --T2
(not -T).
Cheers.
On 21 Nov 2008, at 07:04, Reza Salimi wrote:
> Hi Liang,
> since tfce statistic cannot be modeled by a parametric distribution,
> you need a permutation testing, like randomise to assess its
> significance.
> So, if you want to have a p-value map for your tfce map,
> you need the summary of all the permutations in your randomise
> (i.e., max_statistic of each perm.).
> As you've guessed correctly, what you have now, is the tfce
> statistic image of your FA (thats what your flsmaths did),
> which is not convertible to a p-value map.
> So, you should rerun the randomise with a TFCE (-T) option.
> cheers
>
> On Fri, Nov 21, 2008 at 4:12 AM, liang wang <[log in to unmask]>
> wrote:
> Hi FSL experts,
>
> I have two questions on TFCE method when processing the FA data
> using TBSS.
>
> 1) In the randomise command, I initially didn't add -tfce but use -x
> term and got some uncorrected stat images (also voxelwise p images)
> and FWE corrected images. However, now I want to see the TFCE
> results, just don't rerun the data in terms of taking a long time.
> Considering the information in the TBSS website, I can apply the
> fslmaths command to existing stat images as follows:
>
> fslmaths *_tstat1.nii.gz -tfce 2 0.5 12 newfile (the set of -tfce
> maybe be changed depend on individual investigations).
>
> I find that there is only one generated file (newfile.nii.gz). I
> guess this file is orignial tfce image and basiclly it includes very
> large number (e.g. > 100).
> My question is how to threshold this file or convert the file into p
> images to get whether there is significant voxels.
>
> Any suggestions? thanks.
> Liang Wang
>
>
>
> --
> Liang Wang, Postdoc
> Woodward Lab
> Department of Psychiatry
> University of British Columbia
> BC Mental Health & Addiction Services
> 938 West 28th Avenue
> Vancouver BC V5Z 4H4
> Telephone: 1-604-875-2000 (ext. 4735)
> Fax: 1-604-875-3871
> Email: [log in to unmask]
>
>
>
> --
> G. Salimi-Khorshidi,
> D.Phil. Student, Dept. of Clinical Neurology, University of Oxford.
> [log in to unmask] http://www.fmrib.ox.ac.uk/~reza
> FMRIB Centre, John Radcliffe Hospital,
> Headington, Oxford, OX3 9DU
> Tel: +44 (0) 1865 222466 Fax: +44 (0)1865 222717
>
---------------------------------------------------------------------------
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
---------------------------------------------------------------------------
|