how are you computing the 20% difference? We definitely don't see this, and
Martin has done extensive testing of repeatability.
Bruce
On Wed, 27 Jul 2011, Jessica Liu
wrote:
Hi Martin,
Thanks for getting back to me. Actually I have two young controls who have 20%
differences between two scans a day apart. Visually, there
are not abnormalities for the surfaces and hippocampus in both subjects i.e. on
tkmedit, the color of the hippocampus area (yellow) looks
alright to me. I don't see any motion artifacts either.
Jessica
On Wed, Jul 27, 2011 at 12:15 PM, Martin Reuter <mreu...@nmr.mgh.harvard.edu>
wrote:
Hi Jessica,
I don't think this is normal. Is this a single subject? Of course in a
single subject lots of stuff can go wrong. Are the surfaces correct? And
the hippo label? Are there motion artifacts in the image etc.
Anyway, you should process this with the longitudinal stream:
http://freesurfer.net/fswiki/LongitudinalProcessing
which should increase repeatability.
Best, Martin
On Wed, 2011-07-27 at 09:01 -0700, Jessica Liu wrote:
> Hi,
>
> We found 20% differences in temporal lobe brain volume and ca. 5%
> difference in the hippocampus volume between two data sets of a young
> normal volunteer scanned 2 days apart.
>
> We use the one-step 19 hours recon-all -all procedure and directly sum
> select values taken from the lh.aparc.stats, rh.aparc.stats, and
> wmparc.stats. The values summed were based on information given from
> https://mail.nmr.mgh.harvard.edu/pipermail/freesurfer/2007-April/005000.html
>
> My question is, are these observations normal for Freesurfer? Any
> comments are greatly appreciated. Thanks!
> --
> Pom & Jessica
>
>
>
> _______________________________________________
> 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.
_______________________________________________
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.
