Hi Jessica, I'd recommend to run the -base and the -long on these and see what happens. If you then still see these differences, maybe we can take a look at your data to figure out what causes this. It could be that the WM segmentation fails somewhere. Anyway, the longitudinal stream should help fix these things.
Are these mprages or multi echo mprages? 3T? what coil? Best, Martin On Wed, 2011-07-27 at 18:01 -0700, Jessica Liu wrote: > Hi Bruce, > > Well for one of the subjects, the total temporal lobe volume from the > first scan was 149937 mm3, and the second scan's total temporal lobe > volume was 183121 mm3. These numbers were found by summing the > volumes from the entorhinal, fusiform, parahippocampal, temporal pole, > transverse temporal, and the inferior, middle, and superior temporal > sections found in the lh.aparc.stats, rh.aparc.stats, and wmparc.stats > for the respective scans. Hippocampus volumes were found by summing > the right and left parts found in aseg.stats. > > Jessica > > On Wed, Jul 27, 2011 at 5:37 PM, Bruce Fischl > <fis...@nmr.mgh.harvard.edu> wrote: > 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
