1. Patients with PAH:

* Hemodynamic diagnosis of precapillary pulmonary hypertension: PAPm ≥25 mmHg, PCWP ≤15 mmHg

* Exclusion of group 2,3,4 or 5

2. Patients with CTEPH:

* Hemodynamic diagnosis of precapillary pulmonary hypertension: PAPm ≥25 mmHg, PCWP ≤15 mmHg

* Persistence of thrombotic perfusion defects on pulmonary scintigraphy or angioCT, after 3 months or more of correct anticoagulant therapy

3. Healthy subjects

* No known disease or condition

* Normal lung function, chest x-ray, EKG and blood chemistry and haematology

Cell Proliferation in Pulmonary Hypertension. FDG-PET Comparison Between Patients and Healthy Subjects