Quantification of cerebral A1 adenosine receptors in humans using [18F]CPFPX and PET.
Adenosine is an important neuromodulator. Basic cerebral effects of adenosine are exerted by the A1 adenosine receptor (A1AR), which is accessible in vivo by the novel ligand [F]8-cyclopentyl-3-(3-fluoropropyl)-1-propylxanthine ([F]CPFPX) and positron emission tomography (PET). The present study investigates the applicability of kinetic models to describe the cerebral kinetics of [F]CPFPX in order to quantify A1AR density in vivo. Six healthy volunteers underwent dynamic PET scanning and arterial blood sampling after bolus injection of [F]CPFPX. For quantitative analysis, a standard two-tissue compartment model (2TCM) was compared with a one-tissue compartment model (1TCM) and Logan's graphical analysis (GA). The 2TCM described the cerebral kinetics of [F]CPFPX significantly better than the 1TCM (in all regions and subjects examined). The estimated values of the regional total distribution volumes (DVt) correlated strongly between the 2TCM and GA (linear regression r = 0.99, slope: 1.007). The DVt correlation between the 2TCM and the 1TCM was comparably high, but there was a significant bias towards lower DVt estimates given by the 1TCM (r: 0.99, slope: 0.929). It is concluded that a 2TCM satisfactorily accounts for the cerebral kinetics of [F]CPFPX. GA represents an attractive alternative method of analysis.
Meyer
Philipp T
PT
Institute of Medicine, Research Center Juelich, Juelich, Germany. ph.meyer@fz-juelich.de
Bier
Dirk
D
Holschbach
Marcus H
MH
Boy
Christian
C
Olsson
Ray A
RA
Coenen
Heinz H
HH
Zilles
Karl
K
Bauer
Andreas
A
D058916:Adenosine A1 Receptor Antagonists; D000328:Adult; D000818:Animals; D002540:Cerebral Cortex / Q000000981:diagnostic imaging / Q000378:metabolism*; D005462:Fluorine Radioisotopes / Q000378:metabolism*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D043682:Receptor, Adenosine A1 / Q000378:metabolism*; D013223:Statistics as Topic; D014055:Tomography, Emission-Computed; D014970:Xanthines / Q000378:metabolism*
C468796:8-cyclopenta-3-(3-fluoropropyl)-1-propylxanthine; D058916:Adenosine A1 Receptor Antagonists; D005462:Fluorine Radioisotopes; D043682:Receptor, Adenosine A1; D014970:Xanthines