Pulmonary glucose uptake measured by positron emission tomography in pulmonary hypertension

Abstract

Introduction: Positron emission tomography (PET) is able to visualise increased cellular fluorodeoxyglucose (FDG) uptake. Pulmonary hypertension in patients with advanced lung disease may cause a measurable FDG-uptake in PET. Objectives: We aimed to approach the question whether severity of pulmonary hypertension may be reflected in a different glucose uptake in FDG-PET. Methods: In this retrospective study of 109 patients with end-stage pulmonary disease (COPD, fibrosis), we determined the standardized uptake value (SUV) of predefined regions of interest in lung parenchyma (LP), left (LV) and right ventricle (RV) of the heart, and pulmonary artery (PA) via FDG-PET. Results from right heart catheterization (mean pulmonary artery pressure [mPAP]) pulmonary function test, six-minute walk distance (6MWD) test, and N-terminal pro brain natriuretic peptide (NT-Pro BNP) were collected. Results: We found a linear correlation between mPAP and the SUV of LP, RV, and PA in all patients (r=0.286, p<0.01; r=0.389, p<0.0001; r=0.499, p<0.0001, respectively). There was a negative correlation between of SUV in LP and TLC for patients with COPD, fibrosis and both diseases (r =-0.374, p=0.002; r=-0.532, p=0.0014; r=-0.739, p<0.0001, respectively). No correlation between pulmonary or myocardial FDG uptake and NT-Pro BNP, FVC or 6MWD was found. Patients with mPAP≥25 mmHg expressed a higher SUV of LP, RV, and PA (0.22 vs. 0.29, p=0.013; 0.75 vs. 1.03, p<0.01; 1.07 vs. 1.19, p<0.01, respectively) compared to patients with mPAP<25 mmHg. Conclusion: We found that pulmonary and myocardial glucose uptake correlates positively with severity of pulmonary hypertension in patients with end-stage pulmonary disease.