A novel partial volume correction method for accurate quantification of [18F] flortaucipir in the hippocampus

Abstract

Abstract Background Off-target binding in the choroid plexus (CP) may cause spill-in of the tau PET tracer [18F] flortaucipir into the adjacent hippocampus region. The impact of this spill-in on hippocampal uptake was assessed using a novel partial volume correction method (PVC). Methods PVC was performed on 20 [18F] flortaucipir dynamic PET scans (10 probable AD and 10 controls). Volumes of interest (VOIs) were defined for both hippocampus and CP. The correlation between hippocampal and CP distribution volume (VT), with and without PVC, was determined. Both anatomically defined and eroded VOIs were used. Results For controls, the correlation between hippocampal and CP VT was significantly reduced after using PVC along with an eroded VOI (r 2 = 0.59, slope = 0.80 versus r 2 = 0.15, slope = 0.15; difference: p < 0.05). The same was true for AD patients (p < 0.05). Conclusion PVC together with an optimized hippocampal VOI resulted in effective reduction of CP spill-in and improved accuracy of hippocampal VT.