On 6/15/2022 7:40 AM, Bouchra Guelib wrote:

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Hi,
I wonder if someone can help me to do something similar to that:
" the mean intensity of each FreeSurfer region (ROI) for the 45 subcortical and the 68 cortical regions were assessed the mean intensity of each FreeSurfer region (ROI) for the 45 subcortical and the 68 cortical regions were assessed to obtain SVU".
Also, I found an article that mentioned that " the estimated total intracranial volume (eTIV) is calculated, which is used later for normalization of the volumetric measures".
My questions are:

1) In " gtm.stats.dat" not all subcortical regions are mentioned, why?

which ones are missing?

2) I applied "mri_getmpc" to obtain the mean intensity, however, I could not figure out what I should do after this step to obtain the mean intensity and compute SVU.

Do you mean mri_gtmpvc? the values will be in the gtm.stats.dat file

3) why do they use eTIV, should I use it, and if yes how!

I don't know. It does not make sense to correct an intensity with eTIV.
btw, I assume you've seen this page https://surfer.nmr.mgh.harvard.edu/fswiki/PetSurfer ?

best regards.

--

GUELIB Bouchra: Ph.D. student
Lire Laboratory

University: Constantine 2-Abdelhamid Mehri- Algeria

Alternative email: Guelibbouchra@gmail.com
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