The Impact of the Transmission Pulse Shape in Ultrasound Harmonic Imaging

Suppressing harmonic components in the transmission (TX) pulses is beneficial in ultrasound harmonic imaging (UHI). Compared to bipolar square waves, sinewave pulses can produce less leakage at harmonic frequencies. However, generating a good sinewave or other arbitrary pulse shapes increases the complexity of the TX electronics. As a consequence, 2-level or multi-level square wave pulses are adopted by many ultrasound systems to drive the transducer. This work quantitatively studies the impact of different TX pulse shapes in UHI based on simulations using the k-Wave toolbox. The image quality is evaluated by two metrics: contrast-to-noise ratio and structural similarity based on cyst phantoms. It shows that 8-level square wave pulses achieve comparable image quality compared to sinewave excitations. This study can be a guideline to trade off the design complexity of TX electronics and image quality for UHI.