In vitro ultrasound attenuation and relative backscatter in the rat liver during carbon tetrachloride administration

Ultrasound attenuation and relative backscatter changes of liver tissue induced by Carbon Tetrachloride (CCl₄) administration were investigated in a rat model. Young male Wistar rats (approx. 200 g) were treated with a weekly oral dose of CCl₄ over a period of 11 weeks. This treatment first leads to a fatty liver which then develops into liver cirrhosis. After excision b-mode scans of the livers were performed with a 9 MHz single element transducer. The attenuation values were calculated for selected frequencies within the transducer bandwidth by two different approaches. The averaged frequency dependent relative backscatter values were estimated after compensation for the attenuation in the acoustic path. For both methods a slight decrease (10 %) of the attenuation and a slight increase (15 %) in the relative backscatter were observed as a function of administration time. These changes are similar to the progression of the relevant blood parameters.