Objective To analyze the feasibility of fetal heart volume assisted diagnosis technique in the screening offetal cardiac outflow disease during middle and late pregnancy.Methods One hundred and ninety cases of single pregnantwomen in mid-late pregnancy were underwent ultrasonography in our hospital were selected. The routine two-dimensionalechocardiography was performed on all the fetuses

the fetal heart volume data were collected.The imaing was post-processed bythe fetal heart volume assisted diagnosis technique.Image quality score was performed and the difference of image quality scorebefore and after processing was compared.The correlation between the aortic and pulmonary artery diameters measured by thetwo methods was analyzed by Pearson correlation analysis.The consistency of the two methods was analyzed by Bland-Altmantest

and the intra observer and inter observer repeatability were analyzed as well.Results One hundred and seventy-six（92.63%）pregnant women obtained clear images of the left and right ventricular outflow tract sections of the fetal heart byfetal heart volume assisted diagnosis technique

the aortic and pulmonary artery diameters were measured.The image qualityscores of left and right ventricular outflow tract before and after processing were statistically significant（Z=-6.958

-8.521

both P=0.000）.Pearson correlation analysis showed that the aortic and pulmonary artery diameters measured by two-dimensionalechocardiography and fetal heart volume assisted diagnosis technique were positively correlated（r=0.83

0.79

both P<0.05）.Bland-Altman test showed suggested that the consistency of the two methods in measuring the diameters of aorta and pulmonaryartery was good.The 95% consistency limits were-1.18～1.01 and-1.81～1.03

respectively.In addition

the intraclass correlationcoefficient values of aortic diameter and pulmonary artery diameter measured by fetal heart volume assisted diagnosis technique were all >0.85.Conclusion The fetal heart volume assisted diagnosis technique has a good application value in the screening ofsingle fetal cardiac outflow disease during the middle and late pregnancy.