Tissue shear viscosity measurements using a spectral ratio method

Mechanical properties such as elasticity and viscosity are highly related to tissue pathology state. Images that provide the geometry information of an object as well as its shear elasticity and viscosity are important in clinical applications. In the supersonic shear imaging (SSI) technique, image reconstruction in an inhomogeneous medium could be performed by varying the reconstruction kernel size, which in this article was regarded as the modified supersonic shear imaging (mSSI) method. In this study, we proposed a spectral ratio (SR) method for the reconstruction of shear elasticity and viscosity images. The reconstruction performance of an embedded object was evaluated for three different sizes of kernels, which were 0.308, 1.84 and 3.08 mm with comparison with the results obtained by the SSI method. The mean elasticity and viscosity error in the best reconstruction case using the SR method was 3.2% and 28.45%, respectively, while the mean elasticity and viscosity error in the best case using modify spectroscopy method is 19.56% and 26.36%, respectively. Both SR and mSSI method could provide boundary information of the embedded object. The SR method could achieve a spatial resolution of 0.308 mm in both elasticity and viscosity reconstruction.