I am trying to convert parcellation (cortical) volumes that I acquired through another platform into surface labels using freesurfer. I tried following code to convert the volume with ID 20 from the parcellationvolumes.nii.gz file into a label

mri_cor2label  --i dir/parcellationvolumes.nii.gz --id 20 --l dir/20.label

Although the code runs fine and finishes successfully, whenever I try to open the created label in freeview, it says that the label is empty.

Any idea what I am doing wrong? Do you have an easier way to project all ROI volumes onto the surface?

A second related question: I have run the recon-all for T1 of the subject and it creates rh.pial and lh.pial. I was wondering whether the transformation to go from T1 volume to the surface is saved somewhere and whether I can apply this transformation to convert my cortical volume parcellations into surface parcellations?

Thank you for your help!

Best regards

Julie