The acoustic properties comparison of lipid microbubbles at high ultrasound frequencies

The effect of microbubble size on the acoustic properties of ultrasound contrast agents has been studied over the clinical frequency range (<;10MHz), but comparable research at high frequency is limited. As a further development of high frequency ultrasound in preclinical, intravascular and superficial tissue imaging, this study quantified the attenuation and contrast to tissue ratio (CTR) of two commercial lipid UCAs, Definity and SonoVue, at three populations over the frequency range 12-31 MHz at 20 ± 1 °C using a broadband substitution technique. The attenuation and CTR of the two contrast agents in the native and large microbubbles (MBs) population were found to decrease with frequency and the magnitude of the values for the two contrast agents was comparable at the same number concentration. Over this frequency range, large MBs contributed more than 5dB to the CTR than from small MBs.