Dear FSL-experts,

I recently ran a script multiplying the same binarized mask with several normalized dti_FA images (fslmaths mask.nii.gz -mul norm_dti_FA.nii.gz output.nii.gz). In most of the cases, I got what I wanted: An .nii.gz with a cutout from my normalized dti_FA image. However in some of the cases (which seemed to be totally random), I got a binarized mask which included only high-FA voxels and thus covered just a part of my original mask. Changing the order of my command (fslmaths norm_dti_FA.nii.gz -mul mask.nii.gz output.nii.gz) solves this problem. However, I was wondering whether this is a bug or why the order of my multiplication makes a difference.

Thank you very much. Your help is greatly appreciated.

Best,

Theodor