Ultrasonic Characterization of Tissue Structure in the In Vivo Human Liver and Spleen

Abstract

Tissue characterization attempts to provide quantitative information about the state of disease or health of tissue interrogated by an ultrasound beam. A notable feature of diffuse disease processes of the liver and spleen is disuption of the normal tissue architecture. Infiitration by collagenous tissue changes both the histologic features and acoustic properties of the tissue. A model is presented for these changes as a change in the distribution of scattering elements and a technique for estimating this distribution from analysis of the fre- quency spectrum of the ultrasonic echoes returned from tissue is de- scribed. Results obtained from analysis of digitized ultrasonic wave- forms backscattered from the livers of normal volunteers and patients with diffuse liver disease and from the spleens of normal volunteers and patients with Hodgkin's disease indicate that the mean scatterer spacing, determined from this analysis, gives useful information re- lated to histological features that is not available from the ultrasonic image and, in some cases, can provide a valuable discrimination be- tween normal and abnormal tissue.