| T O P I C R E V I E W |
| vvs4 |
Posted - Nov 02 2010 : 2:18:23 PM
Hi,
We have a question about a particular subject's QA output.
We are looking at the images of the mean of each voxel across time and the standard deviation - and they both show a very blurry ring around the brain. This is one of our first subjects that hasn't had a clear image - this looks awful! However, there is no obvious X, Y, Z motion. We are wondering how to interpret this? What exactly are these images showing? Is there anywhere in the QA report that shows values that match with the images?
You can see the images here:
http://www.vsoch.com/LONG/Pictures/Analysis/BlurryImages.JPG
When we process this functional data for our main faces task, it looks OK. You can view an image here - this is for faces > shapes, .05 uncorrected, no masking, and outliers detected by Art art fed in as a regressor:
http://www.vsoch.com/LONG/Pictures/Analysis/Facesgrshapes05uncorr.jpg
Any knowledge about how to interpret the QA maps (and explain why it is possible to see blurriness in absence of motion) would be greatly appreciated!
Best,
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| 1 L A T E S T R E P L I E S (Newest First) |
| syam.gadde |
Posted - Nov 03 2010 : 09:41:09 AM
The "motion" plots are actually center-of-mass, which may reflect motion, but in some cases may not do it accurately, especially in cases where only part of the brain is included in the field of view. However, a bright red or yellow line bordering the brain is a good indication of motion. Whether it's enough to be concerned about requires more investigation.
However, I'm not sure why there is that cloudy area around the brain in the mean images, which I think is what you are most worried about here.
If you would like to send (privately) the exam number and run number, or create a trouble ticket, we can take a look. |
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