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@INPROCEEDINGS{Kroll:1037885,
      author       = {Kroll, Tina and Miranda, Alan and Drechsel, Alexandra and
                      Klein, Sabina and Beer, Simone and Neumaier, Bernd and
                      Drzezga, Alexander and Rosa-Neto, Pedro and Verhaeghe,
                      Jeroen and Elmenhorst, David and Bauer, Andreas},
      title        = {{F}easibility and reproducibility of awake positron
                      emission tomography with the adenosine {A}1 receptor
                      radiotracer [18{F}]{CPFPX} in moving rats: {C}onsiderations
                      of reference region and route of injection},
      reportid     = {FZJ-2025-01028},
      year         = {2024},
      abstract     = {To prevent motion artifacts in small animal positron
                      emission tomography (PET), animals are routinely scanned
                      under anesthesia or physical restraint. Both may potentially
                      alter metabolism and neurochemistry [1]. This study
                      investigates the feasibility and reproducibility of PET
                      brain imaging in moving rats using the adenosine A1 receptor
                      tracer 18F-CPFPX and subsequent point-source based motion
                      correction [2]. Second, we focus on the optimization of the
                      reference region used for absolute quantification of data
                      and the simplification of radiotracer injection via
                      intraperitoneal administration.Eight male rats underwent six
                      randomized dynamic PET scans each following either an
                      intravenous (i.v.) or intraperitoneal (i.p.) bolus of
                      18F-CPFPX. For both conditions, two subsequent scans were
                      performed under awake condition followed by a scan under
                      isoflurane anesthesia. The outcome parameter BPND determined
                      via the simplified reference-tissue model (reference:
                      olfactory bulb or pons) was evaluated in terms of
                      variability and reproducibility. In vitro 3H-DPCPX
                      saturation autoradiography of the same animals served for
                      validation of in vivo outcome parameters.Route of injection
                      (i.v. versus i.p.) did not have any impact on BPND neither
                      when modelling data with reference region olfactory bulb nor
                      pons. However, 18F-CPFPX uptake and BPND was lower in awake
                      imaging independent of injection route or reference region.
                      In vitro Bmax and 18F-CPFPX BPNDpons correlated
                      significantly (all p<0.01) for i.v. (r=0.81-0.86) and i.p.
                      (r=0.81-0.88) injection route under awake and anesthetized
                      condition. Correlations were slightly superior in comparison
                      to data modelled with the olfactory bulb (r=0.79-0.83).
                      Test-retest stability of BPNDpons after i.p. tracer
                      injection performed best when comparing the different
                      conditions and gave reliable results in awake animals with
                      high test-retest correlations (r=0.99, p<0.01) and an
                      acceptable absolute variability (mean over investigated
                      regions $15.3±5.8\%).Quantitative$ awake small animal PET
                      imaging with 18F-CPFPX is feasible and reproducible. Imaging
                      protocols can be improved by applying a reference region
                      with lower probability of radioactive spill-in from
                      point-sources and practicability can be enhanced by i.p.
                      tracer injection without loss of quantitative accuracy.},
      month         = {Mar},
      date          = {2024-03-12},
      organization  = {19th European Molecular Imaging
                       Meeting, Porto (Portugal), 12 Mar 2024
                       - 15 Mar 2024},
      subtyp        = {After Call},
      cin          = {INM-2},
      cid          = {I:(DE-Juel1)INM-2-20090406},
      pnm          = {5253 - Neuroimaging (POF4-525) / NEURON Cofund - ERA NET
                      NEURON in the area of brain-related diseases and disorders
                      of the nervous system (680966)},
      pid          = {G:(DE-HGF)POF4-5253 / G:(EU-Grant)680966},
      typ          = {PUB:(DE-HGF)6},
      url          = {https://juser.fz-juelich.de/record/1037885},
}