Extensions of nonlinear B/A parameter imaging methods for echo mode

This paper investigates nonlinear B/A parameter imaging in ultrasound echo mode. First, the B/A estimation methods which can be extended to echo mode are identified. The finite amplitude approaches are found to be excellent candidates to assess the nonlinear parameter because of their experimental simplicity, supported by a strong mathematical background. Second, three nonlinear coefficient measurement methods, thus far proposed for applications in homogeneous media, are extended to heterogeneous media. In particular, the simulations show that the extended comparative method (ECM) offers the best results when the probe diffraction effects are taken into consideration. The first experimental images obtained by applying the ECM for two different phantoms are also presented, showing the feasibility of B/A imaging.