Modeling acoustic backscatter from kidney microstructure using an anisotropic correlation function.

Techniques for investigating acoustic backscatter from anisotropic biological tissues are examined. This empirical study combines single-scatter theory with the known elastic properties and histology of the renal cortex to predict the backscatter coefficient from kidney parenchyma. A transverse isotropic correlation model is developed to explain how backscattered energy, which varies with the incident sound wave direction, is related to the anisotropic structure of the tissue. From the results we conclude that renal morphology scatters sound incoherently, and that complex mixtures of scattering structures of different sizes, number densities, and scattering strengths can be distinguished by analyzing backscatter in specific frequency channels--a spectroscopic approach. A K-space description of backscatter measurements from kidney cortex, including the effects of anisotopy, provides further support of our hypothesis regarding sources of acoustic scattering.