Model-based elastography: a survey of approaches to the inverse elasticity problem

Plane-Wave Imaging Improves Single-Track Location Shear Wave Elasticity Imaging

Single-track location shear wave elasticity imaging (STL-SWEI) is immune to speckle bias, but the quality of the images is depth dependent. We hypothesize that plane-wave imaging can reduce the depth dependence of STL-SWEI. To test this hypothesis, we developed a novel technique known as plane-wave STL-SWEI (pSTL-SWEI). To evaluate the pSTL-SWEI's potential, we performed studies on phantoms and excised murine pancreatic tumors. The mean shear wave speeds measured with STL-SWEI and pSTL-SWEI were similar. However, the elastographic signal-to-noise ratio (SNR_e) of pSTL-SWEI elastograms was noticeably higher than that produced with STL-SWEI. Specifically, we observed an improvement in SNR_e ranging from 39.9%-55.1%, depending on tissue stiffness. The spatial resolution of pSTL-SWEI elastograms was 2.7%-12.1% lower than that produced with STL-SWEI. pSTL-SWEI elastograms displayed higher contrast-to-noise ratio (CNR_e) than those produced with STL-SWEI, especially when imaging was performed with low push pulse intensities and low pulse durations.