Positron Emission Tomography With 1 C CGP-12177 to Assess-Adrenergic Receptor Concentration in Idiopathic Dilated Cardiomyopathy

Background. Positron emission tomography (PET) with `GC-labeled CGP-12177 (CGP) has been shown to have the potential to noninvasively measure 13-adrenergic receptor concentration in dog heart. The present study was undertaken to evaluate the clinical value of this technique. Methods and Results. Eight normal subjects and 10 patients with heart failure related to an idiopathic cardiomyopathy were studied. Estimation of 13-receptor concentration was based on a graphic method applied on myocardial PET time-concentration curves obtained after an intravenous injection of '1C-CGP followed 30 minutes later by a coinjection of labeled and unlabeled CGP. The clinical tolerance of these injections was good. Left ventricular concentration of 1-receptors was decreased in patients compared with controls (3.12±0.51 versus 6.60±+1.18 pmol/mL, respectively; p<0.001). This 53% decrease agrees with previous in vitro data. In eight of the 10 patients, the 13-receptor concentration obtained from PET