Ultrasonographic means and method for visualizing the internal structure and composition of an in vivo soft tissue specimen as a function of its effect on the frequency spectrum of an applied complex wave pulse of short duration provided by a single wideband, shock-excited transducer utilized in the pulse-echo mode. Echo trains spatially related to the specimen structure are bandpass filtered to provide a plurality of spectrum signals indicative of the frequency content of each echo train as a function of time. In a first display mode a plurality of three spectrum signals are primary color-coded and combined to present a multicolor B-scan ultrasonogram permitting characterization of tissue specimen locations in terms of their frequency response as related to the color spectrum correlated to the frequency spectrum. In a complementary second display mode providing higher frequency resolution, a larger plurality of spectrum signals are presented in graph form in a monochrome ultrasonogram permitting detailed characterization of a single A-scan line segment of a tissue specimen as a function of its frequency response. Both display modes are enhanced by modifying the spectrum signals to represent the instantaneous power spectrum of the echo train of the applied pulse as affected by the scanned tissue specimen.