“…Moreover, although the nonlinearity of microbubbles was introduced in the due to the most important nonlinear acoustic behaviors of microbubbles under insonation, the nonlinear propagation of echoes through microbubbles was not included in the . Demi et al has observed and characterized the cumulative phase delay between the second harmonic and fundamental component caused by the nonlinear propagation as microbubbles . Tang et al further illustrated the nonlinear distortion of CEUS induced by the nonlinear propagation through microbubbles, which misclassified the tissue signal and could reduce CTR of CEUS .…”