Measurement of Ultrasound Attenuation in Tissues from Scattered Reflections: In-Vitro Assessment of Applicability

Abstract

The attenuation of ultrasound may become a useful parameter in in-vivo tissue characterization. A simple approach using the video signal of A-mode equipment and decompressing the amplitude levels has proven to yield significant information (cf. Thijssen et al. 1980, 1981). Since the A-mode signal contains only disturbed frequency information a better signal for studying the frequency dependence of tissue interaction is of course the radio frequency (RF) echogram. Two parameters may be derived then, i.e. the attenuation per centimeter tissue at a particular frequency (e.g. the center frequency of the transducer), and the frequency dependence of the interaction of ultrasound with tissue expressed by the spectral slope, i.e. the spectral power relative to some internal (i.e. another tissue sample) or external reference power spectrum. The attenuation and the frequency dependence can by summarized by the so-called tissue transfer function, or tissue impulse response (Kak & Dines 1978, Dines & Kak 1979).