title: Reproducibility of non-invasive a1 adenosine receptor quantification in the rat brain using [(18)F]CPFPX and positron emission tomography.
abstract: OBJECTIVE
  The A1AR antagonist 8-cyclopentyl-3-(3-fluoropropyl)-1-propylxanthine ([(18)F]CPFPX) has recently been shown to be a suitable radiotracer for quantitative in vivo imaging of the A1 adenosine receptor (A1AR) in rats. The present study evaluates the reproducibility of non-invasive longitudinal A1AR studies with [(18)F]CPFPX and a dedicated small animal positron emission tomography (PET) scanner.
  
  
  METHODS
  Twelve male Sprague Dawley rats underwent four repeated dynamic PET scans with a bolus injection of [(18)F]CPFPX. A1AR availability was determined by different non-invasive approaches including simplified and multilinear reference tissue (olfactory bulb)-based models and graphical methods. The outcome parameter binding potential (BP) was evaluated in terms of variability and reproducibility.
  
  
  RESULTS
  Repeated estimations of [(18)F]CPFPX BP ND gave reliable results with acceptable variability (mean 12 %) and reproducibility (intraclass correlation coefficients raging from 0.57 to 0.68) in cortical and subcortical regions of the rat brain. With regard to kinetic models, test-retest stability of the simplified reference-tissue model (SRTM) was superior to multilinear and graphical approaches.
  
  
  CONCLUSIONS
  Non-invasive quantification of A1AR density in the rat brain is reproducible and reliable with [(18)F]CPFPX PET and allows longitudinal designs of in vivo imaging studies in rodents.
authors.affiliation: Institute of Neuroscience and Medicine (INM-2), Forschungszentrum Jülich GmbH, 52425, Jülich, Germany, t.kroll@fz-juelich.de.
authors.forename: Tina
authors.initials: T
authors.lastname: Kroll
authors.forename: David
authors.initials: D
authors.lastname: Elmenhorst
authors.forename: Angela
authors.initials: A
authors.lastname: Weisshaupt
authors.forename: Simone
authors.initials: S
authors.lastname: Beer
authors.forename: Andreas
authors.initials: A
authors.lastname: Bauer
mesh_terms: D000818:Animals; D001921:Brain / Q000098:blood supply / Q000000981:diagnostic imaging*; D049268:Positron-Emission Tomography; D017207:Rats, Sprague-Dawley; D043682:Receptor, Adenosine A1 / Q000378:metabolism*; D012039:Regional Blood Flow; D015203:Reproducibility of Results; D014970:Xanthines
chemical_list: C468796:8-cyclopenta-3-(3-fluoropropyl)-1-propylxanthine; D043682:Receptor, Adenosine A1; D014970:Xanthines