Thank you. Regards, Nabin
On Sat, Jun 25, 2016 at 5:36 PM, Bruce Fischl <fis...@nmr.mgh.harvard.edu> wrote: > the mean across both lh.cortex.label and rh.cortex.label should be pretty > close. If you want it to be exact you should weight by area then normalize > > On Sat, 25 Jun 2016, Nabin Koirala wrote: > > Dear Bruce, >> Thank you for the response. So, I more thing if I want to get the mean >> cortical thickness for whole brain I could simply take the mean between >> both >> hemisphere ? If I understood right from the FAQ. >> >> Q. I am trying to measure the global mean cortical thickness (i.e >> combined across hemispheres), how would I do this? >> >> A: One suggestion is to use the surface area of each hemisphere as the >> weighting factor. In which case the global mean thickness including both >> hemispheres would be given by: >> >> bh.thickness = ( (lh.thickness * lh.surfarea) + (rh.thickness * >> rh.surfarea) >> ) / (lh.surfarea + rh.surfarea) >> >> If you use the values in the ?h.aparc.stats, it already factors out the >> 'unknown' region, so you don't have to do it yourself. >> >> >> Regards, >> >> Nabin >> >> >> On Sat, Jun 25, 2016 at 3:29 PM, Bruce Fischl <fis...@nmr.mgh.harvard.edu >> > >> wrote: >> Hi Nabin >> >> unless the areas are the same size, the mean of the areal means >> won't equal the overall mean. >> >> cheers >> Bruce >> On Sat, 25 Jun 2016, Nabin Koirala wrote: >> >> Hi freesurfer team, >> I extracted the cortical thickness values using >> aparcstats2table command and >> I got the cortical thickness values for 34 regions >> and mean cortical >> thickness for each hemisphere. But when I averaged >> the cortical thickness >> from those 34 regions regions it was different than >> the mean cortical >> thickness obtained by aparcstats2table. I would >> expect it to be the same or >> very close but I checked it for more than 100 >> subjects and they are >> significantly different. Am I missing something >> silly here ? >> >> Thank you. >> >> Regards, >> Nabin >> >> >> _______________________________________________ >> 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 > > > 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 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.
