Fibrosing Mediastinitis: a Rare Cause of Unilateral Absent Lung Perfusion on a V/Q Scan

We report a case of a 29-year-old female with a history of asthma, post-partum ARDS, and pulmonary hypertension who presents with severe shortness of breath. The patient describes her shortness of breath as progressive over the past 10 years. Chest radiography and CT angiography of the thorax showed findings consistent with fibrosing mediastinitis with severe stenosis of the left main pulmonary artery. This resulted in appearance of unilateral absent left lung perfusion on quantitative Tc-99-MAA perfusion and Xe-133 ventilation (V/Q) scan.