CTICasesInfundibular Pulmonary Stenosis with Selective Left Pulmonary Artery Enlargement
[...]. Infundibular Pulmonary Stenosis with Selective Left Pulmonary Artery Enlargement. CTICases. Published October 8, 2026. https://cticases.com/c/qrhxm
Imaging findings
The radiograph shows cardiomegaly, a main pulmonary artery segment larger than the aorta, and a large left pulmonary artery, while the right interlobar artery is normal or small. The lateral view shows an enlarged left pulmonary artery and right ventricle. CT confirms a dilated main and left pulmonary artery with a normal-to-small right pulmonary artery. The pulmonary valve is normal, but the right ventricular infundibulum is markedly narrowed and thick-walled even in systole, which echocardiography confirmed. The right ventricle and right atrium are enlarged, and the anterior right ventricular wall is thick.
Key takeaways
Enlargement of the main and left pulmonary arteries with a normal right pulmonary artery is the classic radiographic sign of pulmonary stenosis. The stenotic jet points straight back into the left pulmonary artery, while the right pulmonary artery branches off at an angle. The same pattern can occur with infundibular (subvalvular) stenosis and a normal valve. Infundibular stenosis is also common in tetralogy of Fallot, although this patient did not have tetralogy.
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