HI Stefano, a) using GM instead of eTIV is a different analysis. You ask if a specific structure atrophies above and beyond gray matter. Make sure you know what you are trying to test, then design the model accordingly b) FS works in native space. That being said, the eTIV value get's computed from the transforms that map each image to Talairach space, so using it in your analysis to correct for head size is comparable to doing an analysis in common space.
Best, Martin On Jan 29, 2015, at 2:02 PM, <[email protected]> wrote: > Hi list, > please, I have two questions: > a) subcortical volume correction in cross-sectional studies could be done by > using total GM as covariate instead of eTIV? > b) relatively to group subcortical analysis in cross-sectional studies, the > anatomical images should be necessarily transformed in common space or is > possible to perform the analysis in native space? > The registration in common space should minimize issues due to different head > size. The computation on native space could bias the results considering the > different head sizes among subjects? > Thanks, > > > Stefano > > From: <[email protected]> > Subject: [Freesurfer] eTIV correction and registration in common space > Date: January 27, 2015 2:28:16 PM EST > To: [email protected] > Reply-To: [email protected], Freesurfer support list > <[email protected]> > > > Hi list, > please, I have two questions: > a) subcortical volume correction in cross-sectional studies could be done by > using total GM as covariate instead of eTIV? > b) relatively to group subcortical analysis in cross-sectional studies, the > anatomical images should be necessarily transformed in common space or is > possible to perform the analysis in native space? > The registration in common space should minimize issues due to different head > size. The computation on native space could bias the results considering the > different head sizes among subjects? > Thanks, > > > Stefano > _______________________________________________ > Freesurfer mailing list > [email protected] > https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer > > > The information in this e-mail is intended only for the person to whom it is > addressed. If you believe this e-mail was sent to you in error and the e-mail > contains patient information, please contact the Partners Compliance HelpLine > at > http://www.partners.org/complianceline . If the e-mail was sent to you in > error > but does not contain patient information, please contact the sender and > properly > dispose of the e-mail. > > > _______________________________________________ > Freesurfer mailing list > [email protected] > https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer --------------------------------- Dr. Martin Reuter Assistant in Neuroscience - Massachusetts General Hospital Instructor in Neurology - Harvard Medical School MGH / HMS / MIT A.A.Martinos Center for Biomedical Imaging 149 Thirteenth Street, Suite 2301 Charlestown, MA 02129 Phone: +1-617-724-5652 Email: [email protected] [email protected] Web : http://reuter.mit.edu
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