Ultrasonic characterization of abdominal tissues via digital analysis of backscattered waveforms.

Ultrasonic waveforms backscattered from normal and abnormal livers and spleens were recorded in vivo with the aid of a high-speed data acquisition system. Frequency-domain analysis of the digitized waveforms was employed to derive values for mean spacing of ultrasonic scatterers in tissue. Amplitude-domain analysis yielded measures of mean amplitude and variance, an indication of the distribution of amplitude values. Studies indicated that cirrhotic liver is characterized by a higher mean amplitude, a broader amplitude distribution, and a larger mean scatterer spacing than normal liver. Amplitude- and frequency-domain statistics for livers with other diffuse disease processes or tumor, as well for abnormal spleens. also differed from those of normal tissues. These data give information which may not be evident from B-mode sonograms, and which appears to be related to histological features.