Hello,

Yes, you are right. The second c comes from the centering step. The "wc3c3" in the initial post is what threw me off. The problem is being caused by the CSF mask which after erosion is not left with any voxels leading to the error. Can you check your CSF segmentation by overlaying it on the (normalized) structural image and make sure that segmentation and normalization happened correctly?



Best
Pravesh