[Perfusion lung scan in unexplained pulmonary hypertension]

Thirty-two patients were diagnosed as unexplained pulmonary hypertension by clinical history, physical examination, hemodynamics, pulmonary angiography and perfusion lung scanning. The findings of pulmonary scans in twenty patients (62.5%) showed patchy heterogeneous perfusion defects, which suggested chronic silent pulmonary thromboembolism (CSPT) and in twelve cases (37.5%) demonstrated normal or equally diffuse radionuclide scattering due to primary pulmonary hypertension (PPH). This result corresponded with the pathological data in some of the relevant references. Pulmonary perfusion scan is a noninvasive, safe and simple procedure for determining whether CSPT or PPH is the causative factor in patients with unexplained pulmonary hypertension.