Ultrasound imaging features of pediatric extralobar pulmonary sequestration with torsion: a retrospective...

Extralobar pulmonary sequestration can undergo torsion within the pleural cavity, which represents a rare and the most severe complication in childhood. To date, no data have been published on the use of contrast-enhanced ultrasound (CEUS) in extralobar pulmonary sequestration with torsion.

The objective of this study was to retrospectively analyse the sonographic features of pediatric extralobar pulmonary sequestration with torsion on gray-scale ultrasound (US) and CEUS.

A retrospective observational study was conducted in eight children with clinically and histologically confirmed extralobar pulmonary sequestration with torsion between January 2020 and September 2024. Gray-scale US findings were available for all eight cases, and CEUS features were obtained and reviewed in detail in four of these patients.

All lesions were solitary, with a right-to-left ratio of 5:3. On gray-scale US, torsional extralobar pulmonary sequestration demonstrated a regular morphology and well-defined margins in all cases. Heterogeneous echotexture was observed in five cases, including cystic structures in two cases and linear branching structures in two cases. On CEUS, absence of enhancement in the early pulmonary arterial phase was identified in all four patients (100%). In the delayed bronchial arterial phase, stem-shaped enhancement confined to the base of the mass was observed in three patients (75%), including one case in which a feeding artery was visualised. Peripheral ring-shaped enhancement during the bronchial arterial phase was present in all four cases (100%). Other associated pulmonary findings included pleural effusion (8/8, 100%) and consolidation (4/8, 50%).

On gray-scale ultrasound, extralobar pulmonary sequestration with torsion typically appears as a well-defined mass with a regular shape in the lower thoracic cavity. On CEUS, stem-shaped enhancement at the base of the mass during the delayed bronchial arterial phase may represent a useful imaging feature for predicting extralobar pulmonary sequestration with torsion.