Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9197953 | NeuroImage | 2005 | 13 Pages |
Abstract
The cerebral A1 adenosine receptor (A1AR) has recently become accessible for in vivo imaging using the selective A1AR ligand [18F]CPFPX and PET. For broad application in neurosciences, imaging at distribution equilibrium is advantageous to quantify stimulus-dependent changes in receptor availability and to avoid arterial blood sampling. Here we propose a bolus/infusion (B/I) protocol to assess the total distribution volume (DVt) of [18F]CPFPX under equilibrium conditions. Employing a bolus-to-infusion ratio of 0.8 h, (near) equilibrium conditions were attained within 60 min. The regional DVtâ² given by arterial and venous equilibrium analyses agreed well with conventional two-tissue compartment model analyses (r2 > 0.94 and r2 > 0.84, respectively) and Logan's graphical analyses (r2 = 1.0 and r2 > 0.93, respectively) (n = 4 healthy volunteers). The mean regional DVtâ² values of these equilibrium analyses and of venous equilibrium analyses in additional seven volunteers demonstrated excellent agreement with the results of earlier bolus studies (r2 > 0.98). Error simulations show that minor deviations from true equilibrium are associated with negligible to small DVt errors. In conclusion, [18F]CPFPX shows suitable characteristics for A1AR quantification by B/I PET scanning. Carefully standardized venous equilibrium analyses may substitute arterial analyses and thus considerably enhance applicability of A1AR PET in clinical routine.
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Authors
Philipp T. Meyer, David Elmenhorst, Dirk Bier, Marcus H. Holschbach, Andreas Matusch, Heinz H. Coenen, Karl Zilles, Andreas Bauer,