Hello Freesurfer Experts,

I'm trying to create a ROI based on the peak from a paper. The peak on MNI305 is X=22; Y=-71; Z=22

to use the mri_volsynth I transformed the CRS from MNI to rh.thickness with the formula:

Vrh.thickness*inv(Trh.thickness)*R*T305*inv(V305) (as exemple 8 in https://surfer.nmr.mgh.harvard.edu/fswiki/CoordinateSystems)

To obtain R I used:

fslregister –s fsaverage –mov $SUBJECT_DIR/fsaverage/surf/rh.thickness –reg rh_thickness.dat

So I created my spherical ROI with:

mri_volsynth --template $SUBJECTS_DIR/fsaverage/surf/rh.thickness --pdf sphere --dim 1 1 1 1 --dim 1 1 1 1 --c_ras 54690 -13581 175 --o ROI.mgz

However, when I try to use

mris_fwhm --subject fsaverage --hemi rh --i ROI.mgz --o sphere.sm10.mgh

I receive an error

ERROR: MRISar1: Surf/Src dimension mismatch.

Can someone help me with this?