I am trying to transform a volumetric ROI from MNI152 space to native space. I am doing this in 2 steps. First (1) I am creating a registration file using bb register to create a registration file and then (2) I am using mri_vol2vol to transform volume onto my subject using the registration file I created in step 1.

1. bbregister --s subjid --mov roi_in_MNI152.mgz --t1 --reg register.dat

2. mri_vol2vol --targ subjid/mri/T1.mgz --mov roi_in_MNI152.mgz --reg register.dat --o roi_in_native.mgz

However, the transformed volume is not anatomically positioned where it is supposed to be. Is there an error in my method?

Thank you,

Carlos