RT Journal Article SR Electronic T1 Myocardial β-Adrenergic Receptor Density Assessed by 11C-CGP12177 PET Predicts Improvement of Cardiac Function After Carvedilol Treatment in Patients with Idiopathic Dilated Cardiomyopathy JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 220 OP 225 DO 10.2967/jnumed.108.056341 VO 50 IS 2 A1 Masanao Naya A1 Takahiro Tsukamoto A1 Koichi Morita A1 Chietsugu Katoh A1 Kenichi Nishijima A1 Hiroshi Komatsu A1 Satoshi Yamada A1 Yuji Kuge A1 Nagara Tamaki A1 Hiroyuki Tsutsui YR 2009 UL http://jnm.snmjournals.org/content/50/2/220.abstract AB We evaluated whether myocardial β-adrenergic receptor (β-AR) density, as determined by 11C-CGP12177 PET, could predict improvement of cardiac function by β-blocker carvedilol treatment in patients with idiopathic dilated cardiomyopathy (IDC). Methods: Ten patients with IDC (left ventricular ejection fraction [LVEF] < 45%) were studied. Myocardial β-AR density was estimated using 11C-CGP12177 PET before treatment with carvedilol. Changes of LVEF in response to dobutamine infusion (ΔLVEF-dobutamine) were also measured by echocardiography. Changes of LVEF (ΔLVEF-carvedilol) were evaluated after 20 mo of carvedilol treatment. Results: Baseline myocardial β-AR density significantly correlated with ΔLVEF-carvedilol (r = −0.88, P < 0.001). In contrast, ΔLVEF-dobutamine did not correlate with ΔLVEF-carvedilol (P = 0.65). Myocardial β-AR density was the significant multivariate independent predictor of ΔLVEF-carvedilol (β = −0.88, P < 0.001) among univariate predictors, including functional class (r = 0.76, P < 0.05), plasma norepinephrine (r = 0.85, P < 0.01), LVEF (r = −0.64, P < 0.05), and age as confounding factors. Furthermore, myocardial β-AR density was significantly correlated with plasma norepinephrine (r = −0.79, P < 0.01) and LVEF (r = 0.70, P < 0.05). Conclusion: Myocardial β-AR density is more tightly related to improvement of LVEF-carvedilol than is cardiac contractile reserve in patients with IDC. Patients with decreased myocardial β-AR have higher resting adrenergic drive, as reflected by plasma norepinephrine, and may receive greater benefit from being treated by antiadrenergic drugs.