-- Michael Harms, Ph.D. ----------------------------------------------------------- Conte Center for the Neuroscience of Mental Disorders Washington University School of Medicine Department of Psychiatry, Box 8134 660 South Euclid Ave. Tel: 314-747-6173 St. Louis, MO 63110 Email: mharms@wustl.edu On 12/10/12 12:21 PM, "Douglas N Greve" greve@nmr.mgh.harvard.edu wrote: > >Hi Stan, I don't think you have to correct thickness for head size or >grey matter volume, but you should do so for subcortical volumes. >Whether you use ICV or GM volume or brain volume depends on what you >believe is happening and what hypotheses you want to test. Check out the >paper by Randy Buckner on estimating ICV from the talairach transform: > >http://surfer.nmr.mgh.harvard.edu/fswiki/eTIV?action=AttachFile&do=view&... >rget=buckner2004.pdf > >doug > > >On 12/10/2012 11:34 AM, Berg, S.F. van den wrote: >> >> Hi Freesurfer Experts, >> >> Just to make it sure i have a question about correcting for cranial >>size. >> >> I compared two groups, 100 patients versus 50 Controls. I entered a >> discrete variable 'groups' (Patients: 1 and controls:2) in qdec. For >> cortical thickness difference between these groups, do i have to >> control for total intracranial volume? ICV (intra cranial volume is >> output from aseg2tables) or controlling for another variable which >> estimate total brain volume, like total gray matter or supra tentorial >> volume? >> >> In my correlation analyses, relating cognitive peformance and cortical >> thickness within the patient group. Do i have to control for ICV or >> Total gray matter? besides the variable age, gender and education. >> >> I think only volume differences between groups need controlling for >> ICV, is that correct? >> >> And in my correlation analyses, relating cognitive performance ato >> subcortical volume within the patient group. Do i have to control for >> ICV or Total gray matter? besides the variables age, gender and >>education. >> >> Do you have a reference to a methodological paper, which descibes >> different (anatomical) nuisance factors and their influence on the >> data? Is there a automated correction for brain size in the cortical >> and subcortical freesurfer stream (step of recon -all command)? >> >> Many Thanks, >> >> >> Stan >> >> >> >> _______________________________________________ >> Freesurfer mailing list >> Freesurfer@nmr.mgh.harvard.edu >> https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer > >-- >Douglas N. Greve, Ph.D. >MGH-NMR Center >greve@nmr.mgh.harvard.edu >Phone Number: 617-724-2358 >Fax: 617-726-7422 > >Bugs: surfer.nmr.mgh.harvard.edu/fswiki/BugReporting >FileDrop: www.nmr.mgh.harvard.edu/facility/filedrop/index.html >Outgoing: ftp://surfer.nmr.mgh.harvard.edu/transfer/outgoing/flat/greve/ > >_______________________________________________ >Freesurfer mailing list >Freesurfer@nmr.mgh.harvard.edu >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.