Wavenumber-domain Ultrasonic Imaging of the Bone Cortex Based on Velocity Distribution Estimation

Quantitative ultrasound becomes an emerging and promising tool for bone evaluation in recent years. Time-domain synthetic aperture (TDSA) and phase shift migration (PSM) have been widely used in ultrasonic imaging. Owing to the significant acoustic impedance contrast between the bone and soft tissue, it is challenging for these methods with unique sound velocity hypothesis to yield accurate ultrasound image of cortical bone. Moreover, to perform image reconstruction, TDSA should focus on all points, and PSM needs to extrapolate the received wavefields layer by layer, leading to the relatively high computation cost. To overcome the limitations, this work proposed a wavenumber-domain synthetic aperture method combined with velocity distribution estimation (WD-SA-VE) to accurately and efficiently image cortical bone. The result of phantom experiment validated the effectiveness of WD-SA-VE.