Thomas,
The term 'volume' can get a little confusing. As you noticed, volume- based analysis is not yet implemented in qdec. What this will be is to take a freesurfer volume measure, like hippocampal volume, and use that as the independent variable to regress against, say, age. The output would not be a surface display, as is the case with all current qdec output, but bar graphs (a bar for each subcortical structure).
The 'volume' option referred to in the surface measures menu that you found refers to a file that recon-all can produce, which is just ?h.area times ?h.thickness. But we are not yet convinced that this calculation of cortical volume at a vertex is an accurate or useful measure (without some further adjustments), so currently that option is not recommended within qdec. So you are right in thinking that this morphometry volume analysis is just for volume measurements of the surface, it is not quite yet ready for prime-time, although v4.0.5 produces the ?h.volume files and -qcache will create the ?h.volume.fwhm?.fsaverage.mgh files.
Nick
On Thu, 2008-08-14 at 16:40 -0300, MRI CDPI wrote:
Dear List, I am testing within qdec an analysis of the subcortical volumes and using for this the subjects of the buckner_data.( First of all i am not sure it this is already implemented within freesurfer - in the Design card it says something like 'Volume-Based not yet implemented' ) Well, i created with asegstats2table a table including all subjects and also the gender and age information. With this i saved a qdec.table.dat. Feeding this table into qdec is doing fine, but when in try to run the analysis with morphometry/ volume the program stops because it can´t find the lh.volume.fwhm10.fsaverage.mgh. My question is, how can i create this file within the recon-all .... - qcache? Perhaps this morphometry volume analysis is just for volume measurements of the surface? I would apreciate if somebody could help me out with my doubts! Thanks, Thomas _______________________________________________ Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer