[MINC-users] Slice time correction and justification for aquiring co-planar

[Dylan David Wagner]

Dear Minc Users,


    I've since moved to another center where they have different 
scanning protocols and I'm trying to understand why they do what they do 
and by extension why we did what we did!

    Firstly: For event related fMRI data analysis using SPM, it's 
neccessary to perform slice timing correction (to correct for the fact 
that slices have been aquired at different times over the TR). How does 
fMRISTAT get away with not doing this? I found this in something Keith 
wrote that seems to explain, but I'm afraid I'm not very clear on what 
it means!!!

"Finally, the regressors for the linear model are formed by subsampling 
the convolved stimuli at the slice acquisition times."

    I'm assuming this means it corrects for slice timing issues without 
having to interpolate a new dataset.

   Second: it's the norm here to collect a coplanar volume in addition 
to  functional and anatomical images. The functional data are then 
registered to this coplanar volume which is itself registered to the 
anatomical. Apparently you get a better fit with this intermediary step 
than if you directly registered functional to anatomical.

    Is there some advantage of MINC or our registration packages which 
allows us to skip this step? Raw volumes seem to register great as they 
come off the scanner.

              Thanks,


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