Dear FreeSurfer developers,

I am attempting to use “mri_vol2surf” command to project output from diffusion MRI models (e.g., DTI) onto the cortical surface.

The registration between the diffusion MRI and anatomical space was performed using “bbregister”, and the projection works well for different --projfrac values (e.g., 0 to 1 from the white matter surface).

However, I encountered issues when attempting to use the “—projopt” option to account for partial volume effects. Specifically, I received the following errors:

“reading gm volume fraction from /autofs/space/allegro_002/users/hlee/SANDI/pvf/Tract_HC_001_07222016/pvf.gm.mgz

reading wm volume fraction from /autofs/space/allegro_002/users/hlee/SANDI/pvf/Tract_HC_001_07222016/pvf.wm.mgz

reading csf volume fraction from /autofs/space/allegro_002/users/hlee/SANDI/pvf/Tract_HC_001_07222016/pvf.csf.mgz

error: No such file or directory

error: GM estimation at vno 0 couldn't find enough samples

error: No such file or directory

error: GM estimation at vno 1 couldn't find enough samples

error: No such file or directory

error: GM estimation at vno 2 couldn't find enough samples

error: No such file or directory

error: GM estimation at vno 3 couldn't find enough samples

error: No such file or directory

error: GM estimation at vno 4 couldn't find enough samples

error: No such file or directory

error: GM estimation at vno 5 couldn't find enough samples

error: No such file or directory”

In the directory, I already have “pvf.gm.mgz”, “pvf.wm.mgz”, and “pvf.csf.mgz” files.

I searched the archive and found a similar error reported in this thread:

https://www.mail-archive.com/freesurfer@nmr.mgh.harvard.edu/msg72784.html

I would greatly appreciate any insights or suggestions to resolve this issue.

Thank you in advance for your help!

Best regards,

Hansol Lee