Hi FSL experts,

I have a white matter binary brain mask in standard space and one ROI again in standard space. But this ROI has few voxels which are in white matter but most of the voxels are in grey matter.

I was wondering if there is a way to delete the white matter voxels from this ROI using white matter brain mask, which I already have e.g. I would like to remove only those voxels from this ROI which overlap with this white matter brain mask.

Looks like there are few FSL Mathematical operations e.g. fslmaths etc in FSL, which might be useful but I am not sure how can I use those to do this task.

I would really appreciate any help.