LUNG SEQUESTRATION IN CHILDREN AND ADULTS BY COMPUTED TOMOGRAPHY.

Pulmonary sequestration is a rare congenital malformation of the lungs, characterized by the presence of a dysplastic segment of pulmonary parenchyma that lacks a normal connection to the tracheobronchial tree and receives its blood supply from aberrant systemic arteries—most commonly branches of the aorta. Two types of sequestration are distinguished based on the location of the abnormal lung tissue relative to the visceral pleura: intralobar and extralobar sequestration. Clinical presentation is highly variable, ranging from asymptomatic cases detected incidentally during imaging to symptomatic cases with varying degrees of respiratory or infectious manifestations, depending on the size and location of the lesion. The choice of surgical management depends on the type of sequestration, highlighting the importance of accurate preoperative diagnosis. Currently, contrast-enhanced computed tomography (CT) is the most informative imaging modality for evaluating parenchymal changes, vascular anatomy, and venous drainage patterns. This article provides a concise overview of the etiology and clinical characteristics of pulmonary sequestration and illustrates CT-based parenchymal and vascular features that assist in both diagnosis and differentiation of sequestration types. Parenchymal findings on CT are highly variable, influenced not only by the type of sequestration but also by the duration of recurrent inflammation in the abnormal segment and any associated congenital airway malformations. The most specific diagnostic feature is the identification of an aberrant artery arising from the systemic circulation. Venous drainage and the definition of sequestration boundaries are key imaging criteria for distinguishing between intralobar and extralobar types. However, classification may be challenging in cases with mixed venous drainage into both pulmonary and systemic systems.