title: Test-retest stability of cerebral A1 adenosine receptor quantification using [18F]CPFPX and PET.
abstract: OBJECTIVE
  The goal of the present study was to evaluate the reproducibility of cerebral A1 adenosine receptor (A1AR) quantification using [18F]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. [18F]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.
  
  
  CONCLUSIONS
  Our results suggest that quantification of [18F]CPFPX imaging is reproducible and reliable for PET studies of the cerebral A1AR. Among the outcome parameters the non-invasive measures were of superior test-retest stability over the invasive.
authors.affiliation: Institute of Medicine, Research Centre Jülich, 52425 Jülich, Germany.
authors.forename: David
authors.initials: D
authors.lastname: Elmenhorst
authors.forename: Philipp T
authors.initials: PT
authors.lastname: Meyer
authors.forename: Andreas
authors.initials: A
authors.lastname: Matusch
authors.forename: Oliver H
authors.initials: OH
authors.lastname: Winz
authors.forename: Karl
authors.initials: K
authors.lastname: Zilles
authors.forename: Andreas
authors.initials: A
authors.lastname: Bauer
mesh_terms: D000328:Adult; D001921:Brain / Q000000981:diagnostic imaging* / Q000378:metabolism*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D043682:Receptor, Adenosine A1 / Q000378:metabolism*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014018:Tissue Distribution; D014970:Xanthines / Q000493:pharmacokinetics*
chemical_list: C468796:8-cyclopenta-3-(3-fluoropropyl)-1-propylxanthine; D019275:Radiopharmaceuticals; D043682:Receptor, Adenosine A1; D014970:Xanthines