Re: [Freesurfer] Ventricle-to-Brain Ratio

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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