Thoracic [18F]fluorodeoxyglucose uptake measured by positron emission tomography/computed tomography in pulmonary hypertension

Positron emission tomography (PET) visualizes increased cellular [(18)F]fluorodeoxyglucose ([(18)F]FDG) uptake. Pulmonary hypertension (PH) is conceived of a proliferative disease of the lung vessels. Increased glucose uptake can be quantified as pulmonary [(18)F]FDG uptake via PET imaging. Because the angioproliferative mechanisms in PH are still in need of further description, the aim of the present study was to investigate whether [(18)F]FDG PET/CT imaging can elucidate these pathophysiologic mechanisms in different etiologies of PH. Patients (n = 109) with end-stage pulmonary disease being evaluated for lung transplant were included in this observational study. Mean standardized uptake value (SUV(mean)) of predefined regions of interest in lung parenchyma (LP), left (LV), and right ventricle (RV) of the heart, and SUV(max) in pulmonary artery (PA) were determined and normalized to liver uptake. These SUV ratios (SUVRs) were compared with results from right heart catheterization (mean pulmonary artery pressure [mPAP], pulmonary vascular resistance [PVR]), and serum N-terminal pro-brain natriuretic peptide. Group comparisons were performed and Pearson correlation coefficients (r) were calculated. The [(18)F]FDG uptake ratios in LP, RV, RV/LV, and PA, but not in LV, were found to be significantly higher in both patients with mPAP ≥25 mm Hg (P = 0.013, P = 0.006, P = 0.049, P = 0.002, P = 0.68, respectively) and with PVR ≥480 dyn·s/cm(5) (P < 0.001, P = 0.045, P < 0.001, P < 0.001, P = 0.26, respectively). The [(18)F]FDG uptake in these regions positively correlated also with mPAP, PVR, and N-terminal pro-brain natriuretic peptide. The SUVR of PA positively correlated with the SUVR of LP and RV (r = 0.55, r = 0.42, respectively). Pulmonary and cardiac [(18)F]FDG uptake in PET imaging positively correlated with the presence and severity of PH in patients with end-stage pulmonary disease. Increased glucose metabolism in the central PAs seems to play a certain role in terms of severity of PH. These results suggest that [(18)F]FDG-PET imaging can help understand the pathophysiology of PH as a proliferative pulmonary disease.