New insights into uteroplacental perfusion: quantitative analysis using Doppler and contrast-enhanced ultrasound imaging.

ABSTRACT

OBJECTIVE: To monitor and quantify uteroplacental perfusion in rat pregnancies by Doppler ultrasound (DUS) and contrast-enhanced ultrasound (CEUS). METHODS: Fourteen rats were randomized in two groups (the CEUS group and the control group). On days 8, 11, 14, 17, 19 and 20 of gestation, we used DUS to measure the resistance index (RI), pulsatility index and blood velocity in the uterine, arcuate and umbilical arteries in both groups. On days 14, 17 and 20, one group was also examined by CEUS. Quantitative perfusion parameters were calculated in 4 compartments (mesometrial triangle, placenta, umbilical cord and fetus) and compared. RESULTS: The DUS measurement showed that the RI of the uterine and arcuate arteries decreased (p < 0.01) from day 14 to day 17, while velocity increased each of these arteries (p < 0.01 and p < 0.05, respectively). Quantification of uteroplacental perfusion by CEUS in bolus mode revealed that blood volume and local blood flow increased from day 14 to day 20 in the mesometrial triangle (p < 0.01) and the placenta (p < 0.05). In the CEUS destruction-replenishment mode, the perfusion parameters showed trends similar to those observed in bolus mode. No microbubbles were detected in the umbilical vein or fetal compartments. The weights of pups in the two groups did not differ significantly. CONCLUSIONS: CEUS estimates of placental perfusion complement the data provided by DUS.