25 Jul
2018
25 Jul
'18
10:33 a.m.
The gammas do look different, but it is hard to tell whether they are, eg, changing sign. Not sure what you want me to comment on.
On 7/24/18 2:17 PM, Martin Juneja wrote:
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Just to add some more info here: The peak location of regions, X1 and X2, which I found without including ICV as covariate are very close with the peak locations I found in Gamma_Without_ICV (~5.15), whereas Gamma_With_ICV is almost all over the brain (range -0.6 to +0.6). I am not sure if this additional info adds anything to interpret gamma.mgh with and without ICV as covariate.
On Tue, Jul 24, 2018 at 10:10 AM, Martin Juneja <mj70481@gmail.com mailto:mj70481@gmail.com> wrote:
Hi Dr. Greve, So I checked both. The rstd.mgh files are very similar in both cases (with and without ICV as covariate), but gamma.mgh files are very different for both cases. Here I am attaching screen shot for both cases: Gamma_With_ICV as covariate and Gamma_Without_ICV as covariate. Could you please have a look at the attached screen shots and provide your thoughts/interpretation of this comparison? Thanks. On Tue, Jul 24, 2018 at 9:35 AM, Douglas N. Greve <dgreve@mgh.harvard.edu <mailto:dgreve@mgh.harvard.edu>> wrote: For noise compare the values in the rstd.mgh file, for effect size look in the gamma.mgh file On 07/24/2018 12:27 PM, Martin Juneja wrote: > > External Email - Use Caution > > Hi Dr. Greve, > > Thanks for your quick reply. Could you please give me more details how > can I check this whether its because of noise or its because of less > CV difference? > I am not sure what method/way is the best and commonly used to confirm > these factors. > > Thanks. > > On Tue, Jul 24, 2018 at 7:06 AM, Douglas Greve <dgreve@mgh.harvard.edu <mailto:dgreve@mgh.harvard.edu> > <mailto:dgreve@mgh.harvard.edu <mailto:dgreve@mgh.harvard.edu>>> wrote: > > your results could have vanished after ICV correction for one of > two reasons: the CV difference became less or the values became > noisier (or a combination). So check in your data which one of > those things happened. > > > On 7/23/18 8:30 PM, Martin Juneja wrote: >> >> External Email - Use Caution >> >> Hello experts, >> >> I am interested in identifying regions of interest by comparing >> cortical volume (CV) between controls and patients. >> >> After including age and sex as my covariates, I identified >> regions X1 and X2, which showed significantly lower CV for >> patients (as compared to controls). >> >> But after I include ICV as another covariate, my results show >> that for none of the areas there is any significant difference in >> CV, i.e. my results vanish. >> >> When I checked subjectwise ICV for each group, I found that there >> is almost significant difference (two-sampled t-test, p = 0.067) >> in ICV between two groups, but interestingly mean group ICV for >> patients group was larger compared than mean ICV for controls. >> But as I said earlier, regions X1 and X2 had significantly lower >> CV for patients (as compared to controls), when I didn't include >> ICV as covariate. >> >> Could you please help me in interpreting these results? Is there >> any advice regarding inclusion of ICV as covariate? Or my results >> are purely because of differences in ICV between groups, and >> there is no real findings regarding the regions identified (X1 >> and X2)? >> >> Thanks a lot ! >> >> >> _______________________________________________ >> Freesurfer mailing list >> Freesurfer@nmr.mgh.harvard.edu <mailto:Freesurfer@nmr.mgh.harvard.edu> >> <mailto:Freesurfer@nmr.mgh.harvard.edu <mailto:Freesurfer@nmr.mgh.harvard.edu>> >> https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer <https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer> >> <https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer <https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer>> > > > _______________________________________________ > Freesurfer mailing list > Freesurfer@nmr.mgh.harvard.edu <mailto:Freesurfer@nmr.mgh.harvard.edu> <mailto:Freesurfer@nmr.mgh.harvard.edu <mailto:Freesurfer@nmr.mgh.harvard.edu>> > https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer <https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer> > <https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer <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 <http://www.partners.org/complianceline> > <http://www.partners.org/complianceline <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 <mailto:Freesurfer@nmr.mgh.harvard.edu> > https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer <https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer> _______________________________________________ Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu <mailto:Freesurfer@nmr.mgh.harvard.edu> https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer <https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer>
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