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 <gr...@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 > > > > > > > > > > > > _______________________________________________ > > Freesurfer mailing list > > Freesurfer@nmr.mgh.harvard.edu > > https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer > > -- > Douglas N. Greve, Ph.D. > MGH-NMR Center > gr...@nmr.mgh.harvard.edu > Phone Number: 617-724-2358 > Fax: 617-726-7422 > > Bugs: surfer.nmr.mgh.harvard.edu/fswiki/BugReporting > FileDrop: https://gate.nmr.mgh.harvard.edu/filedrop2 > www.nmr.mgh.harvard.edu/facility/filedrop/index.html > Outgoing: ftp://surfer.nmr.mgh.harvard.edu/transfer/outgoing/flat/greve/ > > _______________________________________________ > Freesurfer mailing list > Freesurfer@nmr.mgh.harvard.edu > https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer > > > The information in this e-mail is intended only for the person to whom it > is > addressed. If you believe this e-mail was sent to you in error and the > e-mail > contains patient information, please contact the Partners Compliance > HelpLine at > http://www.partners.org/complianceline . If the e-mail was sent to you in > error > but does not contain patient information, please contact the sender and > properly > dispose of the e-mail. > >
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