Doug,
Thanks for your reply.
Difference between the two TVV methods ranges between 1-6% Difference between the two TBV methods ranges between 2-4%
Basically, my question is two-fold:
a) what is the most accurate representation of total ventricular volume b) what is the most accurate representation of total brain volume (all parenchyma)
Best,
James
On Thu, Apr 6, 2017 at 3:17 PM, Douglas N Greve greve@nmr.mgh.harvard.edu wrote:
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
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