Gray scale second harmonic imaging of the liver: a preliminary animal study

Gray scale second harmonic imaging (2.5 MHz/5.0 MHz) was evaluated in preliminary animal studies with a new ultrasound contrast agent (FS069). FS069 was administered intravenously in 10 rabbits (6 with normal liver, and 4 with implanted VX-2 tumors) and two woodchucks with hepatocellular carcinomas. The vasculature (including tumor vessels) and liver parenchyma were clearly enhanced at a low dosage (optimal dose was from 0.1 to 0.2 mL/kg) in all cases. Enhancement was reproducible and generally dose-dependent. Tumors were enhanced well during the early phase and tumor enhancement disappeared earlier than that of surrounding normal liver. Arterial phase and portal phase were easily distinguished and patterns of enhancement were diagnostic of the tumors. Gray scale second harmonic imaging is useful in the detection of hepatic tumors and in diagnosis of their hemodynamics.