the values we provide include partial volume correction, so they won't be the same as just counting the number of voxels in a label.

cheers Bruec

On Sat, 23 Mar 2013, Ran Xu wrote:

Dear Freesurfer experts, I used the Index from aseg.txt to get the left thalamus (Index 10), but the real volume I got is different from the size in aseg.txt. Its volume is 5007 in aseg.txt and I programmed a matlab code to find all values equaling to 10 in aparc+aseg.nii. However, the volume I got is 5237 from matlab code.

Could you tell me how to extract the real ROI? I mean its volume number should be the same with the one in aseg.txt?

Thanks.