Assessment of liver and kidney enhancement with a perfluorocarbon vapor-stabilized US contrast agent

Rationale and Objectives. The authors evaluated the time-echogenicity respo nse of liver, kidney, and implanted VX2 tumor after injection of a microbub ble contrast medium and assessed use of an avascular lesion as an internal standard. Materials and Methods. Twenty-one New Zealand White rabbits were studied. T o evaluate use of an internal standard and the dose-response relationship, nine rabbits with 7-day-old avascular liver lesions created by alcohol abla tion received 0.1, 0.25, 0.5, and 1.0 mt of AF0145, a microbubble contrast agent. To evaluate tumor echogenicity, 12 rabbits implanted with VX2 tumor in the liver (six also underwent alcohol ablation) received 0.5 mL of AF014 5. Videodensitometry was used to analyze echogenicity changes over 10 minut es. Results. Echogenicity of the alcohol-ablated liver was not affected by cont rast material administration. Liver and kidney echogenicity relative to abl ation increased linearly with dose, peaking 1 minute after injection and de caying to baseline over 9 minutes. Contrast material administration defined the size and margins of VX2 lesions more clearly. In the arterial phase, t he tumor rim was hyperechoic relative to surrounding liver, becoming isoech oic during the portal venous phase then hypoechoic during the late phase pa renchymal phase. Conclusions. Lesions created by alcohol ablation can he used as an internal standard for quantitative analysis of adjacent tissues. AF0145 enhances pe rfused tissues, including vascular tumors, at gray-scale, real-time ultra-s onography and enhances the liver.