Use of Nakagami statistical model in ultrasonic tissue mimicking phantoms characterization

In order to improve tissue characterization, the probability density function of ultrasonic backscattered echoes which may be treated as random signals, is modeled using Nakagami statistical distribution. Recently, it has been shown that Nakagami statistical model constitutes a quite good model for tissue characterization due to its simplicity and general character. Experiments were performed using a 5MHz linear array connected to a 128 individual channels open research platform (M2M, Les Ulis, France) equipped with individual analog transmitters. Ultrasound images and corresponding RF signals were acquired at different transmit frequencies ranging from 2 to 6 MHz. Transmitted signals had frequency bandwidths of 80 to 90 %. A commercially available phantom was used to mimic tissue backscattering. The analysis was performed on different sizes and locations of the sampling window. The received echoes have been filtered around the transmitted center frequency and around twice the transmitted frequency (2nd harmonic). Acquired RF signals have been analyzed in order to evaluate Nakagami parameter (m), the scaling parameter (Ω) and the probability density function (PDF). These latter results have been compared to those obtained by using Field II software.