To explore the value of prenatal ultrasound in the diagnosis of fetal inferior vena cava malformations by microvascular flow imaging (MV-Flow).

Between June 2020 and June 2021, 22 787 pregnant women from Chengdu Women′s and Children′s Center Hospital undergoing fetal system ultrasound examinations between 20 and 24 weeks were retrospectively analyzed and patients who were prenatally diagnosed with inferior vena cava malformations were chosen. MV-Flow equipment and a multi-section observation technique were used to monitor the inferior vena cava. Spatio-temporal image correlation (STIC) was used to make a definite diagnosis of inferior vena cava malformation. Ultrasound examinations of children or postnatal autopsies were monitored.Comparisons were made between the three systems′ operational times and prenatal diagnosis accuracy.

Prenatal and postnatal examinations were used to diagnose and confirm 67 occurrences of inferior vena cava anomalies. The sonographic results of MV-Flow technology demonstrated that when the IVC was disrupted, the hepatic vein instead flowed directly into the right atrium. An " S" -shaped route could be seen in the left IVC, while a " h" -shaped course could be seen in the double IVC. MV-Flow, multi-section observation, and STIC all had comparable diagnostic efficacy. The average time of MV-Flow, multi-section observation, and STIC were (10.16±2.48)s/case, (34.75±11.04)s/case and (225.11±36.67)s/case, respectively. The difference was statistically significant (Z=126, P<0.01).

MV-Flow, used in prenatal ultrasonography to detect the inferior vena cava, offers good prenatal diagnosis accuracy, is easy to use, and may be widely applied.