Unilateral Pulmonary Artery Agenesis, Stenosis, and Hypoplasia

Two patients with agenesis, one with stenosis, and one with hypoplasia of the unilateral pulmonary artery were studied by three radioisotope lung imaging procedures. In pulmonary artery agenesis, lack of perfusion with homogeneous ventilation was seen in the affected lung. In pulmonary artery stenosis, perfusion was greatly diminished but ventilation was normal in the affected lung. In pulmonary artery hypoplasia, perfusion and ventilation were diminished and there were scan signs of severe airway obstruction on the affected side. By placing the affected lung in the dependent position, perfusion to the involved lung was increased in stenosis and hypoplasia but was unaltered in agenesis.