Unmasking of Agenesis of Right Pulmonary Artery with Unilateral Absence of Perfusion on Lung Scintigraphy

Abstract

We present a rare finding on lung ventilation–perfusion (V/Q) scintigraphy for a woman with longstanding dyspnea. CT of the chest showed volume loss on the right side, which raised concern about possible bronchiolitis obliterans or Swyer–James–MacLeod syndrome; however, the right pulmonary artery could not be visualized. A subsequent V/Q scan showed absence of perfusion and decreased ventilation to the entire right lung, consistent with agenesis of the right pulmonary artery. The patient’s clinical course and imaging features mimicked Swyer–James–MacLeod syndrome, which usually presents with a matched perfusion defect in a single lung or lobe on V/Q scanning. This case highlights the importance of a multimodality imaging approach to achieve a diagnosis.