Yea, the volumetric segmentation is only accurate to 1mm^3, whereas the surface-based has subvoxel accuracy.
doug
Bruce Fischl wrote:
Hi Aaron,
I wouldn't trust the aseg gm labels nearly as much as the surfaces. In our experience they are quite a bit more accurate.
cheers, Bruce
On Mon, 19 Mar 2007, Goldman, Aaron (NIH/NIMH) [C] wrote:
Thanks,
Related to this, I noticed these values tend to be smaller than the "cortical GM" labels generated by the subcortical segmentations (by about 10% in the data I was looking at). I was just curious if there was a known reason why this would be expected.
-Aaron-
-----Original Message----- From: rahul@nmr.mgh.harvard.edu [mailto:rahul@nmr.mgh.harvard.edu] Sent: Monday, March 19, 2007 12:18 PM To: Goldman, Aaron (NIH/NIMH) [C] Cc: freesurfer@nmr.mgh.harvard.edu Subject: Re: [Freesurfer] cortical GM from parcellations
Hi Aaron,
In terms of purely anatomically, to calculate the total GM I would not include the corpus callosum (a white matter structure) or the unknown region (which is an amalgam of subcortical areas).
Best,
rahul
Hi, I wanted to calculate total surface-based cortical GM, and was
wondering if there was a command to do this automatically. If not, and
I
need to add up the volumes in ?h.aparc.stats manually, are there ones
I
should leave out (like unknown, corpus callosum, etc)?
Thanks,
-Aaron-
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