The potential for early diagnosis of pulmonary arterial hypertension using lung iodine-123-metaiodobenzylguanidine (I-MIBG) uptake: A case report.

Previous reports have found evidence that the lung uptake of iodine-123-metaiodobenzylguanidine (I-MIBG) represents pulmonary vascular endothelial function. Therefore, it was believed that the reduced lung uptake of I-MIBG in patients with pulmonary artery hypertension may indicate poor pulmonary vascular endothelial function in those patients. In our previous report, we analyzed the lung uptake of I-MIBG in patients with pulmonary hypertension, and demonstrated that it is lower in patients with pulmonary arterial hypertension (PAH) than in those with chronic thromboembolic pulmonary hypertension and controls, suggesting that reduced uptake of I-MIBG in patients with PAH indicates endothelial dysfunction of the pulmonary artery. In the current report, we describe a 46-year-old woman diagnosed with scleroderma whose lung uptake of I-MIBG was decreased on admission, but she was not diagnosed with pulmonary artery hypertension at that time because her pulmonary artery pressure during right heart catheterization was not elevated. However, she was diagnosed with borderline PAH 2 years later. The lung uptake of I-MIBG was reduced before a reduction in %DLCO was observed. This report suggests that the lung uptake of I-MIBG may be useful for the early diagnosis of pulmonary artery hypertension.