Imaging description

Pulmonary sequestration is uncommon and can be divided into intralobar and extralobar types, depending on specific morphologic features. In general terms, sequestration refers to lung tissue that is isolated from the tracheobronchial tree [1–3]. Intralobar sequestration accounts for 75% of all pulmonary sequestration and consists of an abnormal segment of lung located within otherwise normal lung. Blood supply is via anomalous systemic vessels arising from the aorta (Figures 16.1–16.3), which typically travel within the inferior pulmonary ligament [1–3]. Most intralobar sequestrations are drained by normal pulmonary veins into the left atrium. Intralobar sequestration typically occurs within the lower lobes, more frequently on the left. Air-bronchograms, bronchiectasis, or cavitation can be seen. Although cases can be congenital, most cases are acquired, likely on the basis of early childhood infection.