Prenatal Diagnosis of Pulmonary Artery Sling With HD Live-Flow Render Mode and Spatiotemporal Image Correlation (STIC)

The fetus of a 28-year-old woman was diagnosed as having fetal pulmonary artery sling (PAS) by prenatal ultrasound examination at 24 weeks’ pregnant. Both 2D and 2D color Doppler ultrasound, in the three vessel view, showed the left PA (LPA) originating from the right PA (RPA) and crossing behind the trachea towards the hilum of the left lung to supply the left lung (Figure A,B). 4D color Doppler ultrasound with spatiotemporal image correlation (STIC) and high definition live-flow mode clearly showed the abnormal origin of the LPA arising from the posterior aspect of right PA (Figure C,D).

Figure.

Prenatal images (A–C) and schematic (D) of the pulmonary artery sling (PAS). (A) 2D ultrasound demonstrating the left pulmonary artery (LPA) originating from the right pulmonary artery (RPA). (B) Color Doppler demonstrating the LPA. (C) Imaging of the PAS with 4D color Doppler ultrasound HD live-flow render mode and STIC. AO, aorta; DA, ductus arteriosus; STIC, spatiotemporal image correlation; T, trachea.

PA sling (PAS) is a rare congenital pulmonary vascular malformation with an uncertain embryologic origin and pathogenesis.¹ It can cause different degrees of mechanical tracheal compression and softening, leading to different degrees of tracheal stenosis. Children with PAS can show wheezing, recurrent respiratory tract infections, respiratory distress and even respiratory failure. In many cases there is poor prognosis and high mortality, so prompt diagnosis and timely intervention are essential. PAS can be fully assessed on fetal echocardiography, especially when using STIC and HD live-flow, which can sensitively identify and display the shape of blood vessels in a 3D dynamic mode. Visually displaying the spatial positional relationship of each blood vessel² can improve the prenatal diagnosis rate of PAS.

Availability of Data and Materials

The deidentified participant data will not be shared.

Disclosures

The authors declare no conflicts of interest.

This study was conducted in accordance with the ‘Declaration of Helsinki’ and the ethical standards of the responsible committee on human experimentation (Medical Ethics Committee of Gansu Provincial Maternity and Child-care Hospital).

References

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• 2.   Wang Y, Zhang Y. Fetal vascular rings and pulmonary slings: Strategies for two- and three-dimensional echocardiographic diagnosis. J Am Soc Echocardiogr 2021; 34: 336–351.