A time-aligned plane wave compounding method for high frame rate shear wave elastography

Abstract

Shear wave elastography (SWE) is an established ultrasonic imaging technique, that provides quantitative measurements of tissue mechanical properties. This technique relies on the combination of acoustic radiation force push beams to generate propagating shear waves and ultrafast imaging, which allows high two-dimensional imaging frame rates to capture the induced motion. Utilizing coherent plane wave compounding (PWC) can improve signal-to-noise ratio (SNR) of acquired data. While the image quality improves, the pulse repetition frequency (PRF) is reduced, reaching limiting bandwidths to perform SWE. To address these challenges, a method for making SWE measurements with high PRF and SNR is presented. The idea follows the Time Aligned Sequential Tracking method, proposed to allow SWE with enhanced SNR in conventional clinical ultrasound scanners. The time alignment process is applied here to the full field-of-view, acquired by using plane waves transmitted at different angles. In this way, the full PRF and SNR gains are obtained. Results are shown from experiments in tissue-mimicking phantoms, where motion and extracted shear wave velocity are compared for the traditional and proposed data processing schemes. Preliminary results on arterial phantoms are also discussed, to emphasize the beneficial effects of the method in dispersive geometries.