O’Brien, William D.

The orotic acid dietary “liver lipid” model has successfully been used to study ultrasonic properties in excessively fatty rat livers [O'Brien et al., J. Acoust. Soc. Am. 83, 1159–1166 (1988)]. The model was used again in order to evaluate more fully ultrasound properties within a more condensed (2%–10%) lipid concentration range. The fatty livers were first evaluated in the intact animal (in situ) with an ultrasonic imaging system (≅ 5 MHz) and then the excised (in vitro) livers were evaluated over the 1- to 100-MHz frequency range. Water, lipid, total protein, and collagen were evaluated for each liver. Significant (p < 0.001) correlations of ultrasonic properties (absorption, all attenuation, speed, and Markovian entropy) against tissue properties (water and lipid) were obtained, thus suggesting that the independent measure of texture may relate to basic ultrasonic propagation properties. [Work supported by NIH Grant CS36O29.]