Test-retest stability of cerebral A1 adenosine receptor quantification using [18F]CPFPX and PET

Purpose The goal of the present study was to evaluate the reproducibility of cerebral A(1) adenosine receptor (A(1)AR) quantification using [F-18]CPFPX and PET in a test - retest design. Methods Eleven healthy volunteers were studied twice. Eight brain regions ranging from high to low receptor binding were examined. [F-18]CPFPX was injected as a bolus with subsequent infusion over 120 min. Various outcome parameters were compared based on either metabolite-corrected venous blood sampling [ e. g. apparent equilibrium total distribution volume (DVt')] or a reference region [ ratio of specific to non-specific distribution volume (BP2)]. Results Test - retest variability was low in the outcome measure BP2 ( on average 5.9%) and moderate in DVt' ( on average 13.2%). Regarding reproducibility, the outcome parameter BP2 showed an intra-class correlation coefficient (ICC) of 0.94 +/- 0.1. For DVt' the between-subject coefficient of variation (% CV) was similar to the within-subject % CV ( around 10%), resulting in a poor ICC of 0.06 +/- 0.2. Conclusion Our results suggest that quantification of [F-18]CPFPX imaging is reproducible and reliable for PET studies of the cerebral A(1)AR. Among the outcome parameters the non-invasive measures were of superior test - retest stability over the invasive.