[Freesurfer] issues with the Talairach transformation

Hi all,

I've just started to do cortical thickness analysis on some subjects and I'm noticing some miss-registrations, more specifically the Talairach image is smaller than the target image no matter what subject I look at! I just wanted to make sure if this is something normal and to what extend it's going to effect the individual cortical thickness calculations. I guess I'm not sure how the Talairach trasnformation is used in further steps of the cortical thickness calculation. I've attached example coronal, sagittal and horizontal slices of one of my subjects. I greatly appreciate your advice.

Thanks, Mojdeh Zamyadi, MSc Clinical Research Project Assistant The Hospital for Sick Children 555 University Avenue Toronto ON M5G 1X8