Thank you everyone for your great input. After reading through all of the suggestions and references, I like the idea of using ICV rather than global averages, at least for this current study. However, I do have one more question. All the papers normalize on surface area. If we want to present the Jacobian values, does it make sense to normalize the Jacobian values to the ICV? Or are the Jacobians conceptionally too different from surface areas to do this?
Thank you, Jeff On Fri, Mar 23, 2012 at 1:29 AM, Michael Harms <mha...@conte.wustl.edu>wrote: > > Our reply to that is here > http://bjp.rcpsych.org/content/196/5/414.2.long > > which reminded me of other papers that have also used a global thickness > measure to covary for mean cortical thickness and thereby "address whether > any regional thickness differences were in excess of global cortical > thickness differences between groups" -- see references [1,4] in our > Reply. > > cheers, > -MH > > > Hi Michael and others, > > > > maybe it's this one: > > > > http://bjp.rcpsych.org/content/196/5/414.1.long > > > > best, > > -joost > > > > > > On Fri, Mar 23, 2012 at 2:15 AM, Michael Harms > > <mha...@conte.wustl.edu>wrote: > > > >> > >> Hi Jeff, > >> I personally like the idea of using average thickness as a covariate to > >> control for a reduction in "whole brain" thickness, and have used that > >> approach in a paper. If the Abstract that you mentioned indicated that > >> this is flawed, I'd be curious to know what the reason was... > >> > >> cheers, > >> -MH > >> > >> On Thu, 2012-03-22 at 21:00 -0400, Bruce Fischl wrote: > >> > Hi Jeff > >> > > >> > yes, I think this is still our recommendation for thickness, although > >> > perhaps David Salat can verify. As far as surface area, you might get > >> > Anderson Winkler to send you a preprint of his newly accepted paper on > >> > surface area comparisons and how to do them properly. I would have > >> said > >> > normalize by the 2/3 root of ICV (maybe David can comment on this as > >> well) > >> > > >> > cheers > >> > Bruce > >> > > >> > > >> > On Thu, 22 Mar 2012, Jeff Sadino wrote: > >> > > >> > > Hello, > >> > > For cortical thickness normalizations, Bruce said not to normalize > >> based on a HBM > >> > > abstract > >> > > ( > >> > http://www.mail-archive.com/freesurfer@nmr.mgh.harvard.edu/msg06646.html). > >> Is > >> > > this still the consensus? > >> > > > >> > > For cortical volume, it is pretty standard to normalize to eTIV. > >> > > > >> > > For cortical surface area (jacobian), I couldn't find any > >> information > >> on the wiki. > >> > > Does anyone have any recommendations? > >> > > > >> > > Thank you, > >> > > Jeff > >> > > > >> > > > >> > _______________________________________________ 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. > >> > >> _______________________________________________ > >> Freesurfer mailing list > >> Freesurfer@nmr.mgh.harvard.edu > >> https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer > >> > > > >
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