Ultrasound image based on ultrasound characterization of tissue microstructure of spontaneous rat mammary tumors

Abstract

Experimental results of acoustic backscatter from spontaneous mammary tumors in rats are obtained over the frequency range of 1 to 15 MHz. The power spectrums (dB) from the experimental results are compared to theory in order to obtain information about tissue microstructure. The theoretical power spectrum assumes an isotropic 3-D Gaussian function as the spatial autocorrelation function used to describe the distribution of scatterers in the tissues. The theoretical power spectrum can be shown for small scatterers (diameter less than 0.2 mm) to be proportional to the Rayleigh spectrum times a second-degree polynomial in frequency. Independent values of the average scatterer diameter and scatterer concentration are obtained from the coefficients of the second-degree polynomial. Scatterer sizes and concentrations measured by ultrasound backscatter are compared to histological data. B-mode images are made of the tumors and surrounding tissues with superimposed regions-of-interest (ROIs) parameterized by the scatterer sizes and concentrations. [Work supported by NIH CA 079179.]