Assessment of placental perfusion using contrast-enhanced ultrasound: A longitudinal study in pregnant rabbit.

ABSTRACT

OBJECTIVES: The main aim of the study was to quantitatively characterize placental perfusion using contrast-enhanced ultrasound in a longitudinal study performed in pregnant rabbits. As a secondary objective, we qualitatively assessed the placental perfusion. METHODS: Three pregnant rabbits were used. Contrast-enhanced ultrasound was performed twice for each dam, either on embryo development (ED) day 14, 21 or 28 of pregnancy, under general anesthesia. Both qualitative and quantitative analyses were performed based on ultrasound assessment. RESULTS: Altogether, data from 29 fetuses were analyzed 10 at ED-14; 12 at ED-21, and 7 at ED-28. Placental vascularization was mainly peripheral at the earliest gestational age and became gradually homogeneous within the whole placenta as pregnancy progressed. Intensity parameters and relative blood flows significantly increased with gestational age. The wash-in and wash-out rates were correlated and a significant increase in wash-in compared to in wash-out rates was observed with increased gestational age. CONCLUSION: Contrast-enhanced ultrasound is feasible in animal models and allows qualitative and quantitative analysis of placental vascularization during pregnancy.