Elsevier, Ultrasound in Medicine and Biology, 4(40), p. 685-694
DOI: 10.1016/j.ultrasmedbio.2013.05.019
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We present a surface-based approach to generate shear wave interference patterns, called crawling waves (CrW), within a medium and derive local estimates of biomechanical properties of tissue. In previous experiments, elongated bars operating as vibration sources were used to generate CrW propagation in samples. In the current study, however, a pair of miniature circular vibration sources is applied to the overlying skin to generate the CrW within the medium. The shape and position of the miniature sources make this configuration more applicable for in vivo implementation. A modified ultrasound imaging system is used to display the CrW propagation. A shear speed mapping algorithm is developed using a detailed analysis of the CrW. The proposed setup is applied to several biomaterials including a homogeneous phantom, an inhomogeneous phantom, and ex vivo human liver. The data are analyzed using the mapping algorithm to reveal the biomechanical properties of the biomaterials.