In vitro standard acoustic parameters of ultrasound contrast agents: definitions and calculations

A standardization procedure for in vitro acoustic characterization of ultrasound contrast agents is presented. Two characteristics of particular importance are defined, the backscatter coefficient B_s and a new parameter: scattering to attenuation ratio STAR. The backscatter coefficient characterizes the capacity of the contrast agent to enhance the echogenicity. The scattering to attenuation ratio expresses the ability of the contrast agent to enhance the visualization of the tissue containing the contrast agent and at the same time, to keep the absorption minimal so the acoustic wave travels through the contrast agent and reaches the underlying structures