2D-6 In Vivo Characterisation of Microbubbles using High Frequency Ultrasound

The goal of this project was to determine the utility of microbubble contrast agents in relation to mouse imaging with high frequency ultrasound. The ability to perform quantitative haemodynamic measurements using high frequency ultrasound and microbubbles is dependent on the behaviour of the contrast agent in vivo. The objective of this study was to investigate the acoustic response and kinetic behaviour of the clinical contrast agent Definitytrade in mice exposed to 30 MHz ultrasound. In vitro experiments showed that the agent behaved predominantly as linear scatterers for pressures < 300 kPa and the signal loss after 600 pulses was minimal (< 1 dB). In vivo experiments showed that the peak enhancement and duration of enhancement of the agent increased linearly for doses between 5 and 50 muL/kg. There was up to 9 times increase in peak enhancement above baseline and up to 5 minute duration of enhancement for doses > 50 muL/kg. It is believed that the utility of microbubble contrast agents for quantitative flow imaging in the mouse using high frequency ultrasound is in 5 to 50 muL/kg dose range. To summarize, the characteristics of Definitytrade injected in a mouse and exposed to 30 MHz ultrasound have been investigated