Hi Silvia, qdec does not support any longitudinal analysis (only cross sectional). So I assume you either compare groups cross sectionally (e.g. at baseline) or you constructed your own longitudinal measure (e.g. percent change, within each subject) and then do a cross sectional analysis of that statistic? Both these things should work. I think your qdec table is setup incorrectly?
Best, Martin On Tue, 2011-07-19 at 12:45 +0200, Silvia Juanes wrote: > Dear all, > We are preprocessed our data to perform a longitudinal study using > longitudinal pipeline of Freesurfer 4.5. However, when we try to do > the group-analysis using qdec (Freesurfer 5.1), we obtain the > following error: > > > ERROR: QdecGlmDesign::GenerateContrasts: factor 1 must have 2 levels > ninputs = 64 > Checking inputs > nframestot = 64 > Allocing output > Done allocing > nframes = 64 > Writing to /home/barbara/subjects/qdec/Untitled/y.mgh > gdfReadHeader: reading /home/barbara/subjects/qdec/Untitled/qdec.fsgd > INFO: gd2mtx_method is dods > Reading source surface /home/barbara/subjects/fsaverage/surf/lh.white > ERROR: no contrasts specified. > Error in Analyze: command failed: mri_glmfit > --y /home/barbara/subjects/qdec/Untitled/y.mgh > --fsgd /home/barbara/subjects/qdec/Untitled/qdec.fsgd dods > --glmdir /home/barbara/subjects/qdec/Untitled --surf fsaverage lh > > > > Has anyone experienced a similar problem and is there any way to correct it? > > > Best, > > > > _______________________________________________ > Freesurfer mailing list > [email protected] > https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer _______________________________________________ Freesurfer mailing list [email protected] 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.
