Hi Helen, I would follow these steps http://surfer.nmr.mgh.harvard.edu/fswiki/Xhemi this describes the interhemispheric analysis assuming that you want to study asymmetry. This is not quite your application, but I think it will work well for it. In general, you don't want to simply left-right reverse the pixel data because the atlases used in processing implicitly incorporate any left-right asymmetry that existed in the training data. doug
On 11/20/2012 12:36 PM, Chen, Xiaoyan wrote: > Dear Freesurfer experts, > > I have a general question regarding data > analysis. Our group has collected data from patients with OA, some of them > received treatment on their left leg, some of them on their right leg. We > would like to flip the brain for the people that received treatment on their > left leg to match the right leg group. Next, we would like perform group > analysis on them. My question is, when should we flip the brain for the left > leg group patients? Should we flip the raw images before we do any > preprocessing at the individual level? Or should we flip the first level > contrast images when we get some results for each of these subjects? I tried > to flip the contrast images, but it seems to give me a lot of error at the > second level group analysis level. It says that the flipped contrast image > does not match the unflipped contrast image in orientation. Thank you very > much. > > > Helen > _______________________________________________ > 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 gr...@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.
