as you note, the gtmseg.mgz has higher resolution and several new ROIs.
the higher res is for partial volume correction. The inclusion of pons
to for the possibility of using it as a reference region, which often
happens in AD studies of FDG. Vermis is for use in serotonin studies so
it can be excluded from the rest of cerebellar cortex as vermis might
have some receptors there making is inappropriate to use as a reference
region.
On 10/26/2020 9:55 PM, 蒋袁芳 wrote:
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Hello Freesurfer Developers,
I have some questions about why the first step of PETSurfer needs to
create gtmseg.mgz segmentation.
I noticed that the differences between gtmseg.mgz and aseg.mgz are the
gtmseg.mgz has a higher resolution and also to separate the pons and
the vermis from the brainstem and the cerebellar. I would like to know
whether the reason to create the gtmseg.mgz segmentation is because
the ROI is based on the Pons?
If so, I also have read some other articles that the ROI is based in
other regions. Why does the Freesurfer choose Pons instead? Also, what
is the purpose of separating the vermis from the cerebellar? Is the
reason to create the gtmseg.mgz segmentation just for the system to
run the PVC?
looking forward to your reply.
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