I was wondering if anyone could help me with a problem we've been having. I do research on an UCLA OCD/Depression research study.
We have PET data collected on both the Siemens neuro ECAT 831 and the Siemens ECAT EXACT HR+961. We have run SPM anaysis using both SPM96 and SPM99. SPM analysis on the data group that was run on the 961 seems to be fine.
However, when running the 831 group, we encounter marked activation along the entire ventrical and white matter tract, regardless of which 831 group we use. The pattern of activation (increase) shown looks the same each time; and this pattern does not appear in the decrease (deactivation) analysis. I thought SPM was supposed to exclude these regions?
We have also increased our height threshold to about 1.4 to rule out this ventricular and white matter areas, but few other regions show up.
I was wondering if anyone knew what this problem might be? Does anyone have suggestions for correcting this pattern of activation that always appears?
Thanks
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