Hi Allison, A suggestion is to use the surface area of each hemisphere as the weighting factor. The global average thickness for both hemispheres is then given by:
bh.thickness = (lh.thickness*lh.surfarea + rh.thickness*rh.surfarea) / (lh.surfarea + rh.surfarea). If you use the data in the ?h.aparc.stats, it already discounts the 'unknown' region, so you don't have to worry about that. All the best, Anderson On 08/14/2011 06:12 PM, Allison R. Kaup wrote: > Hi all, > > Please pardon the novice question... but what is the best way to get > global mean cortical thickness (i.e. combined across hemispheres)? I > have used mris_anatomical_stats to get mean thickness separately for > each hemisphere. To get a global mean thickness, would I just take a > simple average (RH mean thickness + LH mean thickness)/2? Or, do I > need some sort of weighted average to account for hemispheric size > diffferences? If so, what would I use as the weight? > > > Thanks! > Allison > > > _______________________________________________ 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.
