Characterization of Definity™ Ultrasound Contrast Agent at Frequency Range of 5–15 MHz

The status of vasa vasorum, which can be imaged using ultrasound contrast agents, is an indication for the progression of atherosclerosis. The preferred ultrasound frequency for this purpose is between 5 and 15 MHz. Therefore, it is essential to have knowledge about the acoustic properties of microbubbles such as elasticity and viscosity to be able to implement the current models for lipid encapsulated microbubbles developed for frequencies used in precordial imaging. In this study, the shell parameters, stiffness Sp and friction Sf, of Definity™ microbubbles have been calculated at frequency range of 5–15 MHz by comparing the theoretical modeling of acoustic bubble response and experimental measurements. Derived parameters are in good agreement with previous estimations on SonoVue™ and Sonazoid™ contrast agent. However, the value of Sf is higher than previously estimated for Definity™ between 12–28 MHz.