Cirrhosis: US images with narrow band filtering.

A new type of ultrasound (US) image was created by first recording unfiltered, backscattered ultrasonic amplitudes to a standard dynamic range prior to narrow band digital filtration of the ultrasonic signal and mapping of the resultant filtered ultrasonic envelope amplitudes. Unlike unfiltered images, those created by narrow band digital filtration permit differentiation between phantoms with different scattering characteristics and normal from cirrhotic human liver in vivo. Significantly different image statistics for normal and cirrhotic liver (P less than .002) were demonstrated in preliminary clinical trials.