Hi Martin, Each subject has 3-6 timepoints. They are all about one year apart. Here's an example of the discrepancy: one subject with 5 timepoints had volumes that ranged from 2.2-2.4. However, from the long_mris_slopes command, the temporal average volume was calculated to be 1.67. Thanks for your help!
-Shannon K. On Thu, Sep 27, 2012 at 6:21 AM, Martin Reuter <mreu...@nmr.mgh.harvard.edu>wrote: > Hi Shannon, > > long_mris_slopes works for surface maps (both thickness and volume > should work). In both cases it should compute the temporal average. > > I have another scripts that works for stats files (long_stats_slopes) in > the same way. > > How many time points do you have, how far apart (equally spaced?). > > Best, Martin > > On Wed, 2012-09-26 at 14:59 -1000, Shannon Kogachi wrote: > > Hi Martin, > > When I used the long_mris_slopes command for the thickness, the > > average thickness calculated in FreeSurfer was pretty similar to > > averaging the values in FreeSurfer. Does this command only work > > thickness measures and not for volume or area? Thanks! > > > > -Shannon > > > > On Wed, Sep 26, 2012 at 2:49 PM, Martin Reuter > > <mreu...@nmr.mgh.harvard.edu> wrote: > > Hi Shannon > > > > You probably mean average thickness. > > My scripts compute the temporal average from the linear fit > > (at mid time), which can be differed from simply averaging > > values. > > Best Martin > > > > Shannon Kogachi <skoga...@gmail.com> wrote: > > Hi, > > I had a question about how the temporal average is > > calculated for subjects with multiple timepoints. I > > used the long_mris_slopes command on a longitudinal > > set of data. However, when I compared the average > > volumes calculated through this command to the average > > volumes calculated in excel after extracting the same > > vertices at the individual timepoints, these values > > did not match up. The average volumes calculated > > through long_mris_slopes were smaller. Please let me > > know if there is a way to explain this discrepancy. > > Thank you! > > > > -Shannon K. > > > > > > > > ______________________________________________________ > > > > Freesurfer mailing list > > Freesurfer@nmr.mgh.harvard.edu > > > > > https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer > > > > -- > > Sent from my phone, please excuse brevity. > > 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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