A New Ultrasound Elastography Method Based on a Variable Windows-Based Numerical Optimization Algorithm

Quasi-static ultrasound elastography is a promising imaging method that analyzes motions from ultrasound images acquired with and without quasi-static forces. Window length is a key parameter for displacement and strain estimation in ultrasound elastography. Traditional methods with fixed windows cannot estimate displacements accurately in areas with uniform and sharp motions simultaneously. In this study, a new ultrasound elastography method based on a variable windows-based numerical optimization algorithm (VW-NOA) is proposed and evaluated using simulated data generated by finite element analysis software (COMSOL3.3). Compared to traditional methods, this proposed approach allows variable windows size based on wavelet analysis on coarse strains calculated by NOA. Thus, it produces fewer errors, especially for areas near boundaries that cross different elastic tissues. We use simulation and phantom experiments to evaluate the method and data and statistical analysis indicate that accuracy or contrast-to-noise ratio (CNR) was improved for VW-NOA compared to original NOA.