Comparison of two novel-strategies to obtain sub-pitch resolution in ultrasound elastography

In elastography, Conventional Linear Array (CLA) - based RF data acquisition can only provide good quality displacement measurements in the direction of beam propagation (axial direction). For obtaining high-precision Lateral Displacement Estimation (LDE), one of the popular methods is by interpolating A-lines in between neighboring RF A-lines. However, acquiring and utilizing the actual data from sub-pitch location will yield fundamentally better estimation. In this paper, we explore a novel method of acquiring and augmenting post-beamformed RF A-line in sub-pitch locations by electronically translating the sub-aperture by activating odd and even number of elements alternatively. We compare this approach to another recently described method where sub-pitch translations of beams were accomplished by actuator-assisted translation of the linear array transducer. The performances of the methods were studied through simulation and experiments on phantoms. The results demonstrate that these methods yield better quality LDE compared to those obtained from interpolation of RF A-lines.