Hi,
I have run tbss_non_FA on MD data and my results suggest that I may have
done something wrong. My FA data is consistent with previous research and
makes good sense, however the results for MD are blank, as in no significant
regions after running randomise. Previous studies have shown MD results
similar to FA.
I have reviewed the all_MD and all_MD_skeletonised outputs and both look
fine. I ran the steps straight from the "Using non-FA Images in TBSS"
section on the TBSS website. I did not correct for scale as I do not think
that this is part of the new version. I used the following randomise command:
randomise -i all_MD_skeletonised -o tbss_MD -m mean_FA_skeleton_mask -d
design.mat -t design.con -n 5000 --T2 -V
where design.con has 2 contrasts to compare between each of our disease
groups and normal volunteers (there are 3 "waves" in design.mat).
When I review even the basic uncorrected p outputs (tbss_MD_tfce_p_tstat1)
the regions of significance seem random and do not line up in the CST as
expected. I do get one small region of significance when running this
process on Lambda1 data, but the location does not make much sense clinically.
Any ideas where I might be going wrong or missing something? Am I missing a
scaling or thresholding step?
Thanks so much for your help!
-Laura
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