On 8/22/17 6:33 AM, Joudy.carter wrote:
Dear experts,
I have suv data and I want to do pve using pet surfer. I have the
following questions and would appreciate your help:
1. The output of mgx is three maps mgx.{ctxgm,subctxgm,gm} these maps
are pvc corrected. I am wondering where can I find pvc corrected maps
for whole brain (white matter and gray matter)?
You can't do this with MG. it gives you maps of tissue types. You can do
it with the RBV output instead of MG. I have been shying away from RBV
because I'm afraid it might be spatially biased.
2. can I register these mgx files to standard space and run voxel-wise
comparison using FSL randomise?
This sounds like you are preparing to to a whole-brain, volume-based
analysis. In my opinion, such analyses using PVC'ed data are invalid
(see the two papers on the petsurfer page for why). The recommended
stream is to do PVC, then run three group analyses, one for the left
hemi, one for the right, and one for subcortical GM. The petsurfer page
documents how to do the surface-based analysis, and I can tell you how
to do the subcort analysis if needed.
3. The output of RBV method is rbv.nii.gz. I want to concatenate all
the rbv files for two groups and run voxel-wise analysis comparison.
Is this possible? The size of these files is pretty large! Do you
recommend better way to study the difference between two groups using
these RBV files?
See above. Generally, you have to do spatial smoothing before voxel-wise
analysis. volume-based smoothing will undo (or worse) the PVC, at least
in cortex.
4. Are these RBV files for white matter and gray matter?
Yes
5. The suv data is an output of single frame PET data with no arterial
blood sampling. Do I still need to re-scale over the pons?
This depend on what you are studying (ligand, disease), so it is more a
question that you need to answer.
Thanks in advance
Joudi
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