Fundamental analysis of lateral displacement estimation quality in ultrasound elastography

Complementary to axial, lateral displacement and strain can provide important information on the biological soft tissues in all applications of elastography. In this paper, the effect of key parameters on the lateral displacement estimation was investigated, in simulations and phantom experiments. The performance of the lateral estimator was evaluated by measuring its associated bias, jitter and correlation coefficient of radio-frequency (RF) signals. Simulation results showed that the bias, jitter and correlation coefficient undergo periodic variations depending on the lateral displacement, with a period equal to the pitch (i.e., adjacent element distance). The performance of the lateral estimation was improved, when a smaller pitch, or a larger beamwidth, was used. The results of the ph4antom experiments were shown to be in good agreement with the simulation findings, including the periodic variation of the performance with lateral displacement, effect of pitch and beamwidth. In conclusion, smaller pitch and wider beamwidth were found to be the key in reducing the jitter error in the lateral displacement estimation.