Proliferative changes in pulmonary vessels may contribute to the development of pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH). Previous studies using [18F]-fluoro-D-glucose positron emission tomography (PET-FDG) imaging in PAH have shown increased cellular metabolism in right ventricle (RV), while the results of uptake in pulmonary artery (PA) and lung parenchyma (LP) are contradictory.The present study aimed to evaluate cellular metabolism in LP, PA and RV by means of PET-FDG in patients with PAH or CTPEH, compared to healthy subjects.
Four groups were evaluated: Healthy controls, n=20; idiopathic PAH (iPAH), n=20; proximal CTEPH (CTEPH-p), n=15; and distal CTEPH (CTEPH-d), n=10. The mean values of standardized 18F-FDG uptake of predefined regions of interest in LP (7 planes per lung in defined anatomical points), PA, RV and left ventricle (LV), were. SUV ratios in patients were related to functional class (FC), exercise tolerance, hemodynamic parameters and serum BNP.
Results and conclusions
The results are shown in Table 1. The RV/LV ratio and AP uptake were significantly correlated with the BNP. AP uptake was correlated with the walking test.
We conclude that patients with precapillary pulmonary hypertension show increased FDG uptake in the right ventricle, particularly those with iPAH. The FDG uptake in both parenchyma and pulmonary arteries were significantly higher in the group with distal CTEPH.