Hi Chikku,
the -qcache command is for cross sectional processing. It is not done in the base and does not need to be done there.
The base is like an additional time point so it does run from the start and even contains some extra steps. 12hrs are not unlikely.
You will need to also run the recon all again on all time points with the -long flag.
Then, once those are processed, you have several options for the analysis, see http://surfer.nmr.mgh.harvard.edu/fswiki/LongitudinalStatistics
we recommend linear mixed effects, described here: http://surfer.nmr.mgh.harvard.edu/fswiki/LinearMixedEffectsModels but in your simple setup (2 time points for each subject), you can also use the direct analysis of atrophy. For that you'd do a) run some processing scripts that compute the rate of change in each subject (e.g. long_mris_slopes or long_stats_slopes) b) use mri_glmfit or qdec to analyze those rates (one for each subject) across groups etc. That is described here: http://surfer.nmr.mgh.harvard.edu/fswiki/LongitudinalTwoStageModel http://surfer.nmr.mgh.harvard.edu/fswiki/FsTutorial/LongitudinalTutorial
Best, Martin
On 02/27/2013 11:19 AM, Varghese Chikku wrote:
Dear all, I am bit confused with the Qdec process. I finished recon all for 2 time points and want to create longitudinal data.From FS tutorial I learned to create within-subject templates for processing,which is running now with recon-all -base <templateID> -tp <tp1id> -tp <tp2id> ... -all. Now,in an other link of tutorial it says ,Qdec needs each subject to have a pre-computed smoothed data for the target surface ,recon-all -s <subjid> -qcache So my first is question is, recon-all -base <templateID> -tp <tp1id> -tp <tp2id> ... -all will do recon-all -s <subjid> -qcache along or I have to run it separately. Second,recon-all -base <templateID> -tp <tp1id> -tp <tp2id> ... -all is almost 12 hrs now and wondering if this is processing images from the very begining. Many Thanks chikku _______________________________________________ Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer