A Mixed Sequence of Diverging Wave and Focused Wave for Ultrasound Cardiac Imaging

Coherent focused wave compounding (CFWC) has been adopted widely in high-end commercial ultrasound scanner to improve the image quality, although its name differs in different companies. In CFWC, each image line is coherently compounded by several focused waves. However, CFWC image would get worse like all other compounding techniques when imaging a rapid moving tissue such as cardiac. The conventional doppler-based motion compensation method does not suit well for CFWC because of the beam pattern differences between the successive focused waves (FWs). In this work, we introduce diverging wave (DW) to CFWC to solve this problem.

I. Introduction

In conventional B-mode ultrasound imaging, ultrasound transducer transmits focused waves to obtain the B-mode image, and each imaging line is beamformed from one focused wave (FW). Since each focused wave only has one focal depth, the conventional B-mode image only gets satisfied image quality in the focal region. To improve the image quality, we can transmit several focused waves with different focal depths in the same position. However, this would lower the frame rate.