Key parameters for precise lateral displacement estimation in ultrasound elastography

Complementary to axial, lateral and elevational displacement and strain can provide important information on the mechanical properties of biological soft tissues. In this paper, the effects of key parameters on the lateral displacement estimation were investigated in simulations and validated in phantom experiments. The performance of the lateral estimator was evaluated by measuring its associated bias, and jitter (i.e., standard deviation). Simulation results showed that the bias and jitter 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 effects of the pitch were found to be greater than those of the beamwidth. The results of the phantom experiments were shown in good agreement with the simulation findings, including the periodic variation of the performance with lateral displacement, effects of pitch and beamwidth. In conclusion, smaller pitches and wider beamwidths were found to be key in reducing the jitter error in the lateral displacement estimation. The same results also hold for tracking in the elevational direction.