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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