[Freesurfer] brain volumes from different freesurfer versions

Dear freesurfers,

We are trying to find a reliable measure of the total brain volume and have been finding it difficult to get a consistent measure across our subjects since they were reconstructed using different versions of freesurfer. Some of our subjects were reconstructed using version v 1.69.2.1 while others used v 1.33

After searching through the mail archive, we decided to use the following command (mri_segstats --seg aseg.mgz --brain-vol-from-seg --sum segVOL)

We are thinking of using the "Brain Segmentation Volume Without Ventricles" from the output file as our total brain volume in our analysis. Will this value be constitent and reliable across the reconstructions using different versions of freesurfer?

Thank you in advance!

Trang