I want to extract the ROI defined by Desikan-Killiany Atlas and save it as a mask on the MNI space.

I try to extract the vertex coordinates by the freesurfer_read_surf and transfer them to MNI. But which surface should I use? 

And maybe some better method.

Thank you for the freesurfer, it is really very good.

Best Wishes!

Yinnan Song

from Peking , China