Dear Christian, thank you very much for your kind help!In whole brain analysis,I set absolute threshold of 0.2, and results seem to be ok. Problems were occured in RBM analysis. When I use this SPM.mat to do ROI analysis, I found areas which cerebellum gray matter volume decreased, the white matter volume increased. Moreover, when I use ROI tools (estimate mean values inside ROI) of CAT12 to extract cerebellum volumes by lpba40 or suit atlas, I found that whose cerebellum gray matter volume decreased obviously, his cerebllum white matter volume increaseed obviously. So I doubt that maybe misclassified of gray or white matter were exist in ROI analysis. So maybe I can use total volume for analysis? But many studies only analyze gray matter by VBM, so I wonder if this has happened to other people, and how to explain and solve it.
And I want to ask which result of ROI analysis by SPM.mat should be used, uncorreted P<0.05, Holm–Bonferroni corrected P<0.05, or FDR P<0.05? Since in a particular analysis many area changed in uncorrected P<0.05, only one area changed in Holm-Bonferroni corrected P<0.05 (but the T value of this area is smaller than another area only in uncorrected P<0.05,this is also very strange), and no area changed in FDR P<0.05. I also want to ask if I use ROI volume for analysis, should I use TIV of each time point to normarlize it, or just use TIV in the baseline to normarlize it, or just use TIV in the baseline as a covariate? In addition, whether volume changes exceed three times of the standard deviation should be excluded?
I'm sorry to disturb your valuable time, and looking forward to your reply. Thank you very much!
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