A Refraction-Aware Pulse-Echo Speed-of-Sound Imaging Method for Convex Transducers

Pulse-echo speed-of-sound imaging is gaining traction as a promising tool to diagnose metabolic dysfunction-associated steatotic liver disease. However, liver screening is generally performed with convex transducers and current pulse-echo speed-of-sound imaging methods often fail to robustly image in far field with such probes, in part due to their neglect of refraction. We introduce herein a novel approach to estimate the local coherence between backprojected ultrasound signals while accurately taking refraction effects into account. Subsequently, our method maximizes the coherence to estimate the speed of sound of the medium. We show with preliminary in-vitro and in-vivo results that our technique is able to correctly estimate local speed of sound in liver-mimicking phantoms and leads to coherent results when imaging the liver of a healthy volunteer.