open-discussion > Voxel values?
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Sep 15, 2011 09:09 PM | Jesse Brown
Voxel values?
I've got a couple points of confusion regarding the intensity
values at each voxel in the .nii parcellation files (eg
tcorr05_2level_all.nii.gz).
1) What are the values at each voxel? I expected they'd be integer values labeling each of the 190 ROIs but they have fractional values instead.
2) Why aren't the values for neighboring voxels the same? I expected that because these ROIs are supposed to be spatially contiguous, neighboring voxels that belong to the same ROI should have identical numerical values/labels.
I'm trying to figure out the best way to threshold ROIs one by one. If I missed some documentation that explains this, feel free to just point me to that. Otherwise, looking forward to your reply. Thanks for sharing these!
Jesse
1) What are the values at each voxel? I expected they'd be integer values labeling each of the 190 ROIs but they have fractional values instead.
2) Why aren't the values for neighboring voxels the same? I expected that because these ROIs are supposed to be spatially contiguous, neighboring voxels that belong to the same ROI should have identical numerical values/labels.
I'm trying to figure out the best way to threshold ROIs one by one. If I missed some documentation that explains this, feel free to just point me to that. Otherwise, looking forward to your reply. Thanks for sharing these!
Jesse
Sep 22, 2011 12:09 AM | Cameron Craddock
RE: Voxel values?
Hello Jesse,
I am very sorry for my late reply. I figured out the problem. In my haste to get the images uploaded I made an error in my script to concatenate all of the parcellation atlases into a single file. This has been corrected and I have uploaded the fix. I have also added documentation for the atlases on the wiki.
I really appreciate you pointing out this issue.
Regards,
Cameron
I am very sorry for my late reply. I figured out the problem. In my haste to get the images uploaded I made an error in my script to concatenate all of the parcellation atlases into a single file. This has been corrected and I have uploaded the fix. I have also added documentation for the atlases on the wiki.
I really appreciate you pointing out this issue.
Regards,
Cameron