qdec analysis sequence - Freesurfer

20 Jun 2012

Hi Jenny, Martin will be the best person to answer your question.
Unfortunately, he is in China now. I think he's back next week.
doug

On 06/20/2012 01:37 AM, Jenny Liu wrote:
> Hello,
>
> I am attempting to use the Qdec Analysis for longitudinal data.
> Specifically, each subject has two timepoints, and belongs to one of
> two groups. Each subject has an accompanying age and
> painUnpleasantness rating. I do not have a 'time in years' variable,
> and instead listed the timepoint as baseline = 0, and post=1.
>
> Thus far, what is done is the PREPROCESSING (listed below as
step #3).
> Thus, every subject has a directory labeled
> "WB101_1.long.WB101_template", and another labeled "WB101_template".
>
> I am on the POSTPROCESSING (listed as step #4). I would like to
> confirm that this is the correct sequence of events to use the Qdec
> Analysis tool to do a mixed linear effects models analysis or mixed
> ANOVA analysis.
>
>
> #1. INITIALIZATION
>
> freesurfer
> tksurfer 005 brainmask.mgz
>
>
> #2. SET SUBJECT DIRECTORY
>
> export
SUBJECTS_DIR=/study/NCCAM/Data/MRI/processed/structural/freesurfer
> cd /study/NCCAM/Data/MRI/processed/structural/freesurfer/
>
>
> #3. PREPROCESSING LONGITUDINAL
>
> recon-all -base ${subject}_template -tp ${subject}_1 -tp
${subject}_2 -all
> recon-all -long ${subject}_1 ${subject}_template -all
> recon-all -long ${subject}_2 ${subject}_template -all
> #4. POSTPROCESSING LONGITUDINAL BY CREATING QDEC TABLE
> #Example file named: long.qdec.table.dat
>
> fsidfsid-basegroupagepainUnptp
> WB101_1WB101_templateMNP65.7211.7  0
> WB401_1WB401_templateLTM5911.6  0
> WB101_2WB101_templateMNP65.728.6   1
> WB401_2WB401_templateLTM59        1
>
>
> #5. OPEN QDEC TABLE
>
> gedit qdec/long.qdec.table.dat
>
>
> #6. CREATE a qdec/measures.Qdecrc file in the qdec directory that
> contains the following line, so that the QDEC analysi know about new
> files.
> #Example file named: measures.Qdecrc
>
> MEASURE1 = long.thickness-avg
> MEASURE2 = long.thickness-rate
> MEASURE3 = long.thickness-pc1
> MEASURE4 = long.thickness-spc
>
>
> #7. CREATE file for each discrete (categorical) factor
> #Example file named: group.levels
>
> MNP
> LTM
>
>
> #8. Pre-smooth fsaverage surfaces
> #Qdec needs each subject to have pre-computed smoothed data for the
> target surface (fsaverage is the default) for each measure
(thickness,
> sulc, area, curv, etc.). Your SUBJECTS_DIR should contain either a
> link or a copy of the 'fsaverage' subject found in your
> $FREESURFER_HOME/subjects directory. Presmoothing the data onto the
> target surface is not part of the normal recon processing
stream, but
> you can easily create this data with recon-all, using the command:
>
> recon-all -s <subject> -qcache
>
>
> #9. Shrink qdec table from a longitudinal form to a cross sectional
> form, in order to run the QDEC group analysis.
>
> long_qdec_table --qdec ./qdec/long.qdec.table.dat --cross --out
> ./qdec/cross.qdec.table.dat
>
>
> #10. PREPARE DATA QCACHE
>
> long_mris_slopes --qdec ./qdec/long.qdec.table.dat --meas thickness
> --hemi lh --do-avg --do-rate --do-pc1 --do-spc --do-stack --do-label
> --time tp --qcache fsaverage
>
>
> #11. Open pial surface of left hemi on average subject. Open
> symmetrized percent change.
> #--qcache flag of long_mris_slopes has been registered and
mapped all
> results to the average subject
>
> tksurfer fsaverage lh pial -overlay
>
$SUBJECTS_DIR/OAS2_0001/surf/lh.long.thickness-spc.fwhm15.fsaverage.mgh
-aparc
>
>
> #12. Run the QDEC analysis on the qdec table:
>
> qdec --table ./qdec/cross.qdec.table.dat
>
>
> #13. Use GUI as indicated by
>
http://surfer.nmr.mgh.harvard.edu/fswiki/FsTutorial/QdecGroupAnalysis
>
>
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--
Douglas N. Greve, Ph.D.
MGH-NMR Center
greve@nmr.mgh.harvard.edu <mailto:greve@nmr.mgh.harvard.edu>
Phone Number: 617-724-2358 <tel:617-724-2358>
Fax: 617-726-7422 <tel:617-726-7422>

Bugs: surfer.nmr.mgh.harvard.edu/fswiki/BugReporting
<http://surfer.nmr.mgh.harvard.edu/fswiki/BugReporting>
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