Preparation of Microbubbles for High Frequency Ultrasound and Their Application in Rat and Rabbit

Purpose: To develop optimal microbubble contrast agents for high frequency ultrasound imaging systems when examining small animals. Materials and Methods: We prepared microbubbles by encapsulate (Perfluoropropane) C₃F₈ into phospholipids shell, and the size distribution of the microbubbles was measured by PSS 780A particle sizing systems. A major peak was observed in the size distribution of the microbubbles at 0.8 μm with mode and median of 0.67 and 0.83 μm, respectively. Vevo 770 system coupled with RMV-707B 30MHz transducer was used to evaluate the quality of the microbubbles. Experiment in vitro by using blood vessel mimic was carried out. Carotid and carotid bifurcation contrast images before and after injecting microbubbles was clearly observed in live rat. Carotid and back leg artery and vein was observed in live rabbit. Conclusion: small size microbubbles less than 1μm is suitable as contrast agent for 30 MHz high frequency ultrasound imaging systems.