Use of frequency diversity and Nakagami statistics in ultrasonic tissue characterization

The Nakagami distribution was recently proposed as a generalized model for the envelope of the backscattered ultrasonic echo from tissue. The paramete rs of the Nakagami model were also shown to be useful in tissue characteriz ation. This paper explores the possibility of enhancing the ability of thes e parameters for tissue characterization through the techniques of diversit y and compounding. Frequency diversity has been used to create multiple ver sions of the envelope, which are then combined. This compounded envelope ha s been modeled, and its parameters have been analyzed. The ability of these new parameters to enhance tissue characterization is studied using compute r simulation and experiments on tissue-mimicking phantoms. Results indicate that the use of frequency diversity and compounding may indeed improve the ability of the parameters of the Nakagami model to separate different numb er densities of scatterers. Therefore, it is suggested that such an approac h may lead to better techniques in ultrasonic tissue characterization.