Imaging of placental circulations by 4D sonography with high-definition flow and spatiotemporal image correlation technology.

Conventionally, two- and three- dimensional color Doppler ultrasonography are used to examine the placental vascularization, but there are limitations in the examinations. In this report, spatiotemporal image correlation (STIC) volume acquisition in high-definition flow, displayed in glass-body mode was used to study the placental vascularization in eight pregnancies. At 20 weeks' gestation, STIC technique allowed visualization of blood flow in the intraplacental branches of the umbilical artery (IPB) and the spiral artery jets in a cardiac cycle. In particular, blood flow from a mega jet penetrating more than half of the placental thickness was demonstrated. Small blood flow from a tertiary order branch of the IPB traversing the placenta and sharply diminishing into the uterine wall was also demonstrated. There were differences in the IPB pattern between normal pregnancies and pregnancies at risk of fetal growth restriction/pre-eclampsia. There were also differences in the appearance of IPB between 20- and 33-weeks' gestation. The results of this report support that it is feasible to use STIC technology to study the placental vascularization. This novel application of STIC technology can increase the understanding of the complex vascularization.