Motion Compensation for High-Frame-Rate Contrast-Enhanced Echocardiography Using Diverging Waves: Image Registration Versus Correlation-Based Method

By using diverging ultrasound waves, a B-mode image can be reconstructed from a single transmission with parallel beamforming. For echocardiography, this approach can provide a frame rate up to 5 kHz, which is two orders of magnitude faster than the most clinical scanners. However, image degradation arising from the lack of transmit focusing when using diverging waves, could not be alleviated by coherent compounding due to the effect of cardiac motion. The motion effects on high-frame-rate contrast-enhanced echocardiography (HFR CEE) when combining diverging waves and microbubble contrast agents were demonstrated in recent studies, with a two-stage correlation-based method and an image registration-based method proposed to enable coherent compounding. The current study compared these two methods for motion compensation in HFR CEE both in vitro and in vivo. For in vitro experiments with a rotating disk phantom, the correlation-based method improved the contrast ratio and contrast-to-noise-ratio by 5 dB and 3 dB, respectively. For the in vivo measurement, the correlation-based method provided a 6-dB improvement in contrast-to-tissue ratio.