I have a few T1 scans that have obvious incorrect registration to mni_average_305. I opened tkregister2 --s subjid --fstal --surfs and I am able to fix the registration, but I wonder how to use the ew registration to recalculate the new ICV. I am interested in doing it with Freesurfer (as I know I could get the matrix and calculate the determinant. I guess I will have to save the transform and rerun some of Freesurfer command to overwrite the old icv value?