Hi Mishkin,

the partial volume correction considers every voxel that borders a voxel with a different label. It then computes what other label is it's most common nbr, then computes the mean non-border intensity for the central and nbr labels in a window (7x7x7 I think), and uses these two means to compute the volume fraction that should be attributed to the central voxel class at that location, and what fraction should be attributed to the nbr voxel class.

cheers, Bruce

On Mon, 1 Dec 2008, Mishkin Derakhshan wrote:

Hi, Are the details of the partial volume corrections described anywhere on the wiki, I couldn't find anything? Is it just a certain percentage of the volume that is disregarded depending on the surface area, or is there a probabilistic labeling of the structures somewhere? Is it possible to get a mask of the structure that includes the partial volume correction, or one of the probabilistic labels (if such a thing exists)? thanks, mishkin

On Tue, Nov 25, 2008 at 1:22 PM, Doug Greve greve@nmr.mgh.harvard.edu wrote:

...

The aseg.stats is computed with a partial volume correction at the boundaries of the structures, tkmedit just counts voxels.

Yuan Xu wrote:

Hi FreeSurfer:

 when I compare a brain structure volume count on the aseg.stats files

with a volume of same structure measured using tkmedit "Segmentation Label Volume Count" feature to display on TkMedit Tools window. They are closer but not the same, usually about 3 to 10% difference. Why?

Thanks,

Yuan

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