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

The β-adrenoceptor (β-AR) plays an important role in heart failure. Recently, the new tracer (S)-[11C]CGP12388 has been developed. It displays excellent properties for investigation of the cardiac β-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 β-AR density in patients with idiopathic dilated cardiomyopathy (IDC) can be estimated using (S)-[11C]CGP12388 PET. Myocardial β-AR density was investigated in six patients with IDC and six age-matched healthy controls, using (S)-[11C]CGP12388 PET. β-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). This study indicates that PET with (S)-[11C]CGP12388 is applicable for the measurement of myocardial β-AR density in patients. A highly significant reduction in β-AR density was found in patients with IDC compared with healthy controls. (orig.)