Simplified quantification of cerebral A 1 adenosine receptors using [ 18 F]CPFPX and PET: Analyses based on venous blood sampling

[ 18 F]CPFPX was proposed as a novel ligand for in vivo quantification of cerebral A 1 adenosine receptors (A 1 AR) using positron emission tomography (PET). The present study investigates the applicability of non‐invasive non‐compartment analyses to quantify the [ 18 F]CPFPX total distribution volume ( DV   ′ t ) without arterial blood sampling. Five healthy volunteers underwent dynamic PET (90 min) with arterial and venous blood sampling after [ 18 F]CPFPX bolus injection. Area under curve (AUC) analysis and Logan's graphical analysis (GA) were performed employing venous blood samples as non‐invasive analyses. AUC analysis without data extrapolation (AUC r ) and venous GA were also applied on voxel‐level to generate parametric images. A conventional two‐tissue compartment model (2TCM) using arterial blood samples served as reference method. Regional DV   ′ testimates provided by venous AUC and GA analyses and 2TCM demonstrated very high agreement (venous AUC vs. 2TCM: r 2 = 0.968, linear regression slope = 0.943; venous GA vs. 2TCM: r 2 = 0.972, slope = 0.906). Although on voxel‐level the venous AUC r and GA analyses were affected by a slight negative bias, they were still very highly correlated with the 2TCM (voxel‐wise venous AUC r vs. 2TCM: r 2 = 0.969, slope = 0.858; voxel‐wise venous GA vs. 2TCM: r 2 = 0.959, slope = 0.867). The proposed non‐invasive analysis methods (particularly venous GA) allow reliable quantification of human [ 18 F]CPFPX PET studies. In populations with altered metabolic/kinetic properties, the applicability of venous sampling has to be separately verified. The applicability of [ 18 F]CPFPX PET in basic and clinical neurosciences will be considerably enhanced by the avoidance of arterial blood sampling. Synapse 55:212–223, 2005. © 2005 Wiley‐Liss, Inc.