Nonlinear Ultrasonic Parameter in Tissue Characterization and Imaging

Abstract

In the wide applications of ultrasound in medicine, the ultrasonic imaging is used extensively in the medical diagnosis. The linear parameters such as acoustic impedance, sound velocity and attenuation are used for human tissue characterization in the conventional clinical ultrasonic imaging systems. However, in recent ten years many works have shown that the important nonlinear acoustic effects can be produced at the biomedical frequencies and intensities. 1, 2 These include the finite amplitude wave distortion, harmonic generation, extra-attenuation and sound saturation. The acoustic nonlinearity parameter B/A is the basic parameter to describe these nonlinear phenomena. The existence of nonlinear effects of ultrasound waves on biological media can accelerate the sound losses and limit the amount of sound power diliverable to the media. Especially, our previous work indicated that the value of the nonlinear parameter of tissues was found to be related to their structural characteristics. Therefore, nonlinear ultrasonic parameter B/A of biological media may become a new parameter in tissue characterization and imaging, thus a valuable tool for medical dignosis.KeywordsNonlinearity ParameterPathological TissueTissue CharacterizationPorcine LiverSound PowerThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.