that looks right. how different are the values?
On 04/05/2017 10:58 AM, Gullickson, James wrote:
Hello all,
I want to calculate a Ventricle-to-Brain ratio (VBR) as a measure of parenchymal atrophy using Freesurfer version 5.3.0. I have tried to go about this using the aseg.stats output (using asegstats2table), but am running into inconsistencies.
The basic calculation for VBR is:
(Total Ventricular Volume/Total Brain Volume) * 100
i.e. Bigler, E. D. (2013). Traumatic brain injury, neuroimaging, and neurodegeneration. /Frontiers in human neuroscience/, /7/, 395.
What is the best way to get Total Ventricular Volume (TVV) and Total Brain Volume (TBV) for this calculation? I have tried several ways, which lead to different values:
TVV = left lateral ventricle + left inf lateral ventricle + right lateral ventricle + right inf lateral ventricle + 3rd ventricle + 4th ventricle + 5th ventricle + choroid plexus
which gives me a different result than
TVV = BrainSegVol - BrainSegVolNotVent
and for TBV
TBV = TotalGrayVol + CorticalWhiteMatterVol
which differs from
TBV = BrainSegVolNotVent
Thank you for your help,
James Gullickson
Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer