Myocardial β-adrenoceptor downregulation in idiopathic dilated cardiomyopathy measured in vivo with PET using the new radioligand (S)-[11C]CGP12388

Purpose. The beta-adrenoceptor (beta-AR) plays an important role in heart failure. Recently, the new tracer (S)-[C-11]CGP12388 has been developed. It displays excellent properties for investigation of the cardiac beta-ARs in vivo with positron emission tomography (PET). Furthermore, the simple production method allows its use in a routine clinical setting. The aim of this study was to investigate whether decreased myocardial beta-AR density in patients with idiopathic dilated cardiomyopathy (IDC) can be estimated using (S)-[C-11]CGP12388 PET. Methods. Myocardial beta-AR density was investigated in six patients with IDC and six age-matched healthy controls, using (S)-[C-11]CGP12388 PET. Results. beta-AR densities of 5.4 +/- 1.3 pmol/g (mean +/- SD) were observed in patients; these values were significantly lower than those observed in healthy controls (8.4 +/- 1.5 pmol/g, p < 0.005). Conclusion. This study indicates that PET with (S)-[C-11]CGP12388 is applicable for the measurement of myocardial beta-AR density in patients. A highly significant reduction in beta-AR density was found in patients with IDC compared with healthy controls.