¹⁸F-FDG uptake of the right ventricle is an important predictor of histopathologic diagnosis by endomyocardial biopsy in patients with cardiac sarcoidosis

Background: The aim of this study was to determine whether right ventricle (RV) ¹⁸F-fluorodeoxyglucose (FDG) uptake can predict positive findings of endomyocardial biopsy (EMB) in patients with cardiac sarcoidosis (CS). Methods: 70 consecutive patients with clinically diagnosed CS who had undergone FDG PET were registered in the present study. Patients without EMB (n = 42) were excluded. Ultimately, 28 patients were studied. EMB samples were obtained from the RV septum. We evaluated the FDG uptake on six segments (RV, left ventricle anterior, septal, lateral, inferior, and apex). Results: Positive EMB was found in six patients (21%). Patients were divided into two groups according to positive (n = 12 [43%]) or negative (n = 16 [57%]) RV FDG uptake. Patients with positive RV FDG uptake had a significantly higher frequency of positive EMB than those without (42% vs. 6%, P = 0.024). On the other hand, there was no EMB-predictive value for the FDG uptakes in the other five segments, the cardiac metabolic volume, total lesion glycolysis, left ventricular ejection fraction, or any electrocardiogram findings. Conclusions: FDG uptake of the RV but no other heart segment was associated with positive EMB in CS patients. The presence of RV FDG uptake could improve the rate of positive EMB up to 42% in patients with CS.