It’s always a good idea to divide the volumes by ICV (or add ICV as a regressor). This is very unlikely, but what if your controls happened to have smaller heads than your patients? For peace of mind, I’d correct by ICV. Cheers, /Eugenio
-- Juan Eugenio Iglesias http://www.jeiglesias.com
From: freesurfer-bounces@nmr.mgh.harvard.edu freesurfer-bounces@nmr.mgh.harvard.edu on behalf of Carly McIntyre-Wood mcintc10@mcmaster.ca Date: Monday, July 8, 2024 at 12:06 PM To: freesurfer@nmr.mgh.harvard.edu freesurfer@nmr.mgh.harvard.edu Subject: [Freesurfer] Is ICV needed as a covariate if matched between groups
External Email - Use Caution Hi there,
I am investigating differences in hipp/amyg volume between a patient and HC sample and am wondering if there is any reason I would still need to include ICV as a covariate if the groups do not differ on ICV (p=.793).
Thanks so much, Carly