Multi-Frequency Regularized Approach for Simultaneous Estimation of the Acoustic Nonlinearity Parameter and Attenuation Coefficient

The acoustic nonlinearity parameter (B/A) could enhance conventional ultrasound diagnostics in diseases associated with changes in fat tissue content. Recently, a simultaneous estimator of the B/A and the attenuation coefficient (AC) in pulse-echo was introduced, which was based on fitting measurements derived from backscattered data from a dual-energy model to a nonlinear model using the Gauss-Newton Levenberg-Marquardt algorithm (GNLM). However, the GNLM algorithm presented high sensitivity to the initial guess values. This paper improves the Gauss-Newton method by using data from several tone-burst transmissions at different center frequencies rather than only one narrowband tone-burst. In addition, it is combined with a total variation regularization approach (GNTV). The results in simulated and experimental phantoms suggest that incorporating regularization and increasing the number of transmission frequencies improves robustness compared to the GNLM method by accurately estimating B/A values (mean relative error less than 13% in the experiments).