Reducing meningeal OTS contamination in cerebellum and target regions has opposing effects
inferior cerebellar gray matter)
After we observed evidence that meningeal OTS with MK6240 spills into target ROIs, (such as ERC, the MetaROI) and the reference region often used for this tracer (inferior cerebellar gray matter) we devised approaches to remove meningeal OTS from cortical regions and from the reference region. The cohort-specific ‘whole OTS’ mask, which was created to include all of the meninges, was used to mask MK6240 scans to remove OTS before edge-preserving spatial smoothing. Compared to our standard MRI-guided processing, masking with the whole OTS mask yields lower SUVRs (negative ΔSUVR relative to our standard processing approach) in target regions, presumably due to successful reduction of meningeal OTS spill-in in target regions (