Novel Approach to Repeated Arterial Blood Sampling in Small Animal PET: Application in a Test-Retest Study with the Adenosine A1 Receptor Ligand [(11)C]MPDX

PURPOSE: Small animal positron emission tomography (PET) can be used to detect small changes in neuroreceptor availability. This often requires rapid arterial blood sampling. However, current catheterization procedures do not allow repeated blood sampling. We have developed a procedure which allows arterial sampling on repeated occasions in the same animal. PROCEDURES: Eleven male Wistar rats were two times catheterized via a superficial branch of a femoral artery and scanned with [(11)C]MPDX and blood sampling. PET images were co-registered to a magnetic resonance imaging (MRI) template. Regional tracer distribution volumes (V(T)) in the brain were calculated by the Logan analysis. The procedure was repeated after 1 week. RESULTS: Surgery was successful in 90 % of the cases, and discomfort was minor. The V(T) data showed small differences between test and retest, low between subject variability, and a strong agreement between and within subjects. CONCLUSION: Repeated quantitative imaging with a high reproducibility is possible with this approach.