Grating Lobe Suppression for Ultrasound Angle-Compounded Ultrafast Imaging

The frame rate of ultrasound imaging (US) is determined by the imaging depth and the number of transmit/receive (T/R) events. One way to achieve an ultrafast frame rate is by reducing T/R events. This can be achieved by utilizing an angle-compounded ultrafast imaging (ACUI) method which utilizes planar wave fronts. Due to ultrafast imaging capability, quantitative tissue stiffness measurement and the full blood characterization could be realized. However, ACUI method suffers from grating lobes (GLs) occurred during multiple angle compounding. To suppress the production of GLs, we analyzed the beam pattern properties of the ACUI method and derived imaging parameter related to GL location. We then determined the receive aperture function that could most efficiently suppress GL production. The obtained receive beam pattern was found to have reduced side lobe levels. This is due to the aperture weighting function being convolved to the receive aperture function. As a result, GL production was effectively suppressed without sacrifice to frame rate. To verify the presented model and the proposed method, beam simulation was conducted and its results were compared to theoretical values. In addition, point target imaging simulation was conducted using Field II to visualize the performance of GL suppression. Simulation results demonstrated that the proposed method could successfully remove the interference caused by GLs while simultaneously preserving frame rate.