Real-Time Placental Perfusion on Contrast-Enhanced Ultrasound and Parametric Imaging Analysis in Rats at Different Gestation Time and Different Portions of Placenta

OBJECTIVES: To quantitatively analyze placental perfusion in a rat model at different gestation time and different portions of placenta by real-time contrast-enhanced ultrasound (CEUS) and parametric imaging analysis. MATERIALS AND METHODS: Sixty pregnant rats at different gestation time (15 dys,17 days and 20 days) were injected intravenously with microbubbles (5×10(5) microbubbles /ml, 1.0 ml/kg), and cadence contrast pulse sequencing (transmission frequency of 7 MHz, mechanical index 0.18) was performed. Dynamic enhancement changes in placenta at different gestation time and different portions of placenta were measured and enhancement parameters analyzed with software. Correlation between enhancement parameters and average area densities of placenta vascular compartment was compared. RESULTS: The pattern and real-time sequence of enhancement in uterus and placenta were clearly depicted by CEUS. The time-to-peak enhancement was earlier in central portion than that in peripheral portion (12.30±6.33s vs 36.26±10.65 s, p = 0.005), and peak intensity of enhancement is much higher in central portion than that in peripheral portion (30.20±2.85 dB vs 20.95±6.25 dB, p = 0.000). The peak intensity of enhancement at day 15 (27.70±4.47 dB) was lower than that at day 17 (30.20±2.85 dB, p = 0.042) and at day 20 (31.85±4.41 dB, p = 0.015) of gestation. Significant correlation between average area densities of vascular compartment and the peak intensity of enhancement was identified in placenta at different gestation time (p<0.05). The average area densities of vascular compartment was higher in central portion than that in peripheral portion and has significant correlation with peak intensity of enhancement of the two potions (p<0.01). CONCLUSION: CEUS is feasible to depict real-time sequence and quantitative parameters of perfusion in different portion of placenta at different gestational time in a rat model.