Dear all,
Related to the bug that was reported in 2011 (see http://www.mail-archive.com/freesurfer%40nmr.mgh.harvard.edu/msg19821.html) with the way that surface-based volumes and areas were calculated in Freesurfer versions 5.1 and earlier, I’d like to confirm that region-of-interest measures obtained using those earlier versions (e.g. when exporting the volume / surface area to tables using aparcstats2table) were unaffected by this bug (i.e. rerunning qcache should not change ROI-based results).
2. I’d like to also confirm that otherwise, for vertex-based analyses, it should be sufficient to run ‘recon-all subject –qcache’ using a more recent version of freesurfer in order to obtain accurate measures for data that was originally processed using 'recon-all –all' with an earlier version of freesurfer (I have data that was originally processed with version 4.4 and other data that was processed with version 5.1 that I would like to now examine in a surface-based manner).
3. The bug was related to how the measures were converted to standard space - I’d like to therefore confirm that when doing surface/vertex-based analyses, it is not necessary to use total brain volume as a covariate (whereas it is for ROI-based analyses).
Many thanks, and all the best, Narly.