Modified Regularized Wavelength Average Velocity Estimator for normal excitation setup.

Crawling Waves Sonoelastography (CWS) is an ultrasound elastography approach for the Shear Waves Speed (SWS) estimation. Several studies show promising results for tissue characterization. The algorithms used to calculate the SWS have been commonly implemented considering an opposing vibration sources to the side of the tissue of interest. However, implementing this mechanical setup has important limitations considering the geometry of the body. For that reason, a propagation from the top to the surface can be useful. Previous estimators such as Phase Derivative have been modified and tested in phantom studies, however, the presences of artifacts limited the performed of the SWS map. In this study, the Regularized Wavelength Average Velocity Estimator (R-WAVE) technique is modified and evaluated (RWm) to be used for normal propagation. The results of heterogeneous simulations and phantoms experiments showed consistent results with the literature (ie: Simulations Max Bias PDm 11.64 % • RWm 10.21 %, Max CNR PDm 37.82 dB • RWm 44.42 dB, Phantom Experiments Max Bias PDm 15.42 % • RWm 13.99 %, Max CNR PDm 24.14 dB • RWm 26.40 dB). The result of this study shows the potential of RWm to characterize the stiffness of the tissue as well as to differentiate tumors on in vivo applications.Clinical relevance This study presents a modification of the regularized shear wave speed estimator based on crawling waves sonoelastography approach for medical tissue analysis. This technique can be used to discriminate benignant from malignant tumors.