I would use the TVV


On 04/06/2017 06:28 PM, Gullickson, James wrote:
> 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 <mailto: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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--
Douglas N. Greve, Ph.D.
MGH-NMR Center
greve@nmr.mgh.harvard.edu
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