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Hi FreeSurfer team,

would anyone have some information regarding my question arounf Infant FreeSurfer volumes? Thanks for your help.

Best, Florent

----- Mail original ----- De: k3ops@free.fr À: freesurfer@nmr.mgh.harvard.edu Envoyé: Lundi 14 Juin 2021 15:16:08 Objet: Infant FreeSurfer: volumes

Hi FreeSurfer team,

I using the latest version of Infant FreeSurfer to assess brain volumes on very young kids. When looking at the brain volume (aka 'BrainSegVolNotVent') extracted from the aseg statistical file I got a very different volume than doing the pixel count (weighted by pixel resolution). For example: - BrainSegVolNotVent: 1174.5 - PixelCount: 1250.8

With standard FreeSurfer (on adults) I was used to get similar volumes when comparing aseg stat file and pixel count.

Is that expected? Why there is a discrepancy between the two way of assessment? I know some other structures are not based on pixel count based on FreeSurfer documentation, but looks like brain volume called 'BrainSegVolNotVent' was not impacted: https://secure-web.cisco.com/18xtJXsGCEPg1_wrBSQsSBwz6uROe4aI7h1jXl1Renz46cq...

Thanks.

Florent