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Dear Freesurfer's experts, I tried to use PETSurfer to correct partial volume effect on my FDG PET images, testing both Muller-Gartner and RBV corrections. I ran the commands specified in PETSurfer website and used the two following commands for both MGX and RBV corrections respectively: mri_gtmpvc --i PET.nii.gz --reg register.dof6.lta --psf-col 5.51 --psf-row 5.51 --psf-slice 5.9 --seg gtmseg.mgz --default-seg-merge --auto-mask PSF .01 --mgx .01 --o ./gtmpvc.output mri_gtmpvc --i PET.nii.gz --reg register.dof6.lta --psf-col 5.51 --psf-row 5.51 --psf-slice 5.9 --seg gtmseg.mgz --default-seg-merge --auto-mask PSF .01 --rbv --o rbv.output.orig 1) However, I found that cortical output mgx.ctxgm.nii.gz of MGX correction encompass more than just GM and values at the boundaries of mgx.ctxgm.nii.gz seem to me very high or aberrant. 2) Concerning RBV correction, output rbv.nii.gz seems to me following more precisely the GM ribbon. However contrary to what is said in PETSurfer website, rbv.nii.gz seems to be in the anatomical space (not in native PET) at the resolution of gtmseg.mgz. How then map rbv.nii.gz to the anatomical space when mapping the volume to the surface ? 3) What are the advantages/inconveniences of RBV vs GMX ? 4) Would it be beneficial to upsample native PET to the anatomical resolution before launching gtmpvc in order to preserve the high resolution of the anatomical tissues during partial volume correction ? Thank you. Best, Matthieu
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