To assess the value of tracing the regional pulmonary venous flow in ultrasonic diagnosis of fetal anomalous pulmonary venous drainage (APVD).

Forty-one fetuses with APVD diagnosed by fetal echocardiography at Hebei Reproductive Maternity Hospital from January 2015 to December 2019 were selected retrospectively. In ultrasonic examination, the fetal lung was roughly divided into four regions: the left upper 1/2, left lower 1/2, right upper 1/2, and right lower 1/2 lung fields. The pulmonary vein branches in the four regions of 41 fetuses with APVD were tracked and located by Color Doppler Flow Imaging. The relationship between the proximal end of pulmonary vein branches and the left atrium and the final drainage location was observed.

A total of 19 372 fetuses were examined, of which 41 (0.2%) were diagnosed as having APVD without other intracardiac malformations. In the 41 fetuses with APVD, the distal branches of the pulmonary vein in the left upper 1/2, left lower 1/2, right upper 1/2, and right lower 1/2 lung fields returned to the left superior pulmonary vein, left inferior pulmonary vein, right superior pulmonary vein, and right inferior pulmonary vein, respectively. The four pulmonary veins in 36 fetuses with total anomalous pulmonary venous drainage (TAPVD) were not connected to the left atrium, of which 34 showed the "convergence sign" behind the left atrium. Pulmonary veins in 25 cases with supracardiac TAPVD returned to the superior vena cava. There were seven cases of intracardiac type, of which the pulmonary veins returned to the right atrium directly in one case and through the coronary sinus in six cases. The pulmonary veins in two cases with cardiac infracardiac TAPVD returned to the inferior vena cava. There were two cases of mixed type, of which the left pulmonary veins returned to the superior vena cava and the right pulmonary veins returned to the inferior vena cava in one case, and the left pulmonary veins returned to the superior vena cava and the right pulmonary veins returned to the right atrium in another case. There were five cases of partial anomalous pulmonary venous drainage (PAPVD). The right superior pulmonary vein returned to the right atrium directly in one case and the superior vena cava in two cases. Two right pulmonary veins returned to the right atrium in one case. There was variation of three left pulmonary veins in one case, with the superior branch returning to the superior vena cava.

Pulmonary vein branches can be scanned more comprehensively and be positioned more accurately by the application of regional flow tracing, which could help to improve the diagnostic accuracy of fetal anomalous pulmonary venous drainage.