The application of high definition flow imaging in fetal hemodynamics.

Objective: This work aims to investigate the application of high definition flow imaging (HD-flow) in fetal hemodynamics, and establish reference range of hemodynamic parameters in fetal with different gestational ages. Materials and Methods: A thousand of normal pregnant women were divided into five groups: 18-22, 23-27, 28-32, 33-37, and 38-40 gestational weeks. Color Doppler flow imaging (CDFI) and HD-flow were adopted to display the heart structure and measure the blood flow velocity. The pulmonary vein display results were scored. The results of HD-flow and CDFI were compared. Results: The catheter peak velocity of fetal mitral, tricuspid, aortic, pulmonary artery, aortic arch, ductal arch, the inferior vena cava, pulmonary vein, and venous catheter increased continuously with the increase of gestational age, showing a linear correlation. HD-flow was superior to CDFI on the display of pulmonary vein in 18-22,23-27, and 28-32 weeks (p < 0.05), but was not in 33-37 and 38-40 weeks. HD-flow was an accurate positioning method for the pulmonary veins. Conclusion: BD-flow can make accurate evaluation of fetal hemodynamics and the demonstration of low blood flow, such as pulmonary venous, is better than CDFI. Pulmonary veins can be accurately positioned with BD-flow. HD-flow can demonstrate the main blood vessels of the whole fetal circulation and can display the spatial relationship of the blood vessels. It is of important clinical significance in hemodynamic study.