18-FDG uptake on PET-CT and metabolism in pulmonary arterial hypertension

Abstract

Background: Proliferative changes in pulmonary hypertension can contribute to the development of idiopathic pulmonary arterial hypertension (iPAH). Energy needed to support cell proliferation may rely on aerobic glycolysis (Warburg effect). Image assessment of cell proliferation in PAH with FDG PET/CT (18F fluorodeoxyglucose positron emission tomography/computed tomography) have shown increased cellular metabolism in right ventricle (RV), while the results in pulmonary artery (PA) and pulmonary parenchyma (PP) are contradictory. In this study we evaluated the relationship between cellular metabolism in PA, RV and PP assessed with FDG PET/CT and the metabolic profile in plasma in patients with iPAH.

Methods: We evaluated 12 patients with iPAH who underwent PET/CT scanning and 18F-FDG uptake (SUV) in predefined regions of interest were correlated with clinical and hemodynamic parameters, as well as with levels of plasma metabolites. as well as with levels of plasma metabolites assessed by quantitative targeted metabolomic studies using liquid chromatography (LC) coupled to mass spectrometry.

Results: The RV SUV correlated with pro-BNP, 6MWD and cardiac index. Patients with iPAH had increased levels of isoleucine, 15-Hydroxyeicosatetraenoic acid (15-HETE), Glutamic acid and diacylglycerol 36:3 (DG 36:1) among other metabolites that were correlated with FDG uptake in FDG PET/CT (Table 1)

Conclusions: In iPAH, the intensity of FDG uptake in pulmonary arteries, right ventricle, and lung parenchyma is associated with systemic parameters that reflect increased cell metabolism. Overall, our findings support the notion of increased cell proliferation in iPAH.