Optimal Transmission Frequency Selection Base on Scattering Cross Section for Ultrasound Contrast Harmonic Imaging

In ultrasound contrast imaging, the bubble size is essentially time varying, which makes the power of bubble echoes decrease in time. The echo strength bubble is dominated by resonance, which is bubble size and driving frequency dependent. To optimize SNR, the imaging frequency must be changed adaptively. An analytical technique, named SCS (scattering cross section) method, for optimal transmission frequency selection is proposed. The optimal transmission frequency is selected to be the frequency that the total SCS of a given bubble mixture is maximized. Based on scattering theory of micro bubble, the SCS of micro bubble can be computed analytically. For quantifying the performance of the SCS method, a power improvement factor of the optimal transmission frequency is defined. The optimal transmission frequency and improvement factor predicted by the SCS method for test cases with different bubble size distributions are presented to show the properties of the SCS method. To show the correctness of the SCS method, improvement factors of the test cases are validated using simulation signals, which are generated by BubbleSim using the optimal transmission frequency predicted by the SCS method.