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Dear FSL experts, I am looking at a set of DTI images in terms of FA, MD, L1 and RD (L2+L3)/2 images. I didn't get any significant TBSS result for FA, MD, L1, however, when I ran TBSS on RD images, I got a corrected p of 0.002 for the same contrast (patient > control) and same design matrix. When I check the tfce correct p stats, and threshold them at p<0.05 (in fslview, I put down 0.95), it is pretty much the "entire" RD skeleton was significant, which is really awkward. I went back and visually check the raw RD images, normalized RD images, and RD skeleton, everything was normal. However, I still feel something is wrong, so here is my tbss_non_FA pipeline. 1. copy the L2 images and L3 images for each subject, and use fslmaths to derive the average of these two. 2. creat a RD folder contaims all the Rd images, and make sure the naming is the same as images in "origdata" 3. Run tbss_non_FA RD 4. Run randomise -i all_RD_skeletonmised -o tbss_RD -m mean_FA_skeleton_mask -d design.mat -t design.con -n 500 --T2 -V Did I miss any step? I read some of the FSL threads that I might need to scale the RD images. By the way, the intensity in my RD skeleton image ranges from 0 to 0.001. Kindly advise. Yi-Shin