03/04/2026
UPAA – Unilateral Pulmonary Artery Atresia:
Axial CT images (mediastinal and lung windows) demonstrate absence of one(Rt) pulmonary artery with a hypoplastic ipsilateral (rt) lung, reduced vascular markings, and relative volume loss. The contralateral lung appears relatively hyperexpanded, likely compensatory. Findings are consistent with unilateral pulmonary artery atresia (UPAA), which may be detected incidentally on imaging.
Learning Points:
-UPAA is a rare congenital anomaly that may remain asymptomatic and be discovered incidentally in adulthood.
-Key CT features include absence of the pulmonary artery, ipsilateral lung hypoplasia, and reduced vascularity, with contralateral compensatory hyperinflation.
-Patients may present later with dyspnoea, recurrent infections, haemoptysis, or pulmonary hypertension.
-Important to recognise as it can be misinterpreted as chronic pulmonary embolism or post-infective changes.
-Management is usually conservative, but complications such as haemoptysis or pulmonary hypertension may require targeted intervention.
