Abstract:

To study the dynamic enhancement changes of the inferior vena cava (IVC) and hepatic vein with grayscale contrast enhancement and to explore its clinical value. MethodsAn in vivo animal model was studied using low mechanical index (MI) in conjunction with dynamic contrastenhanced sonography. SonoVueTM(0.1?mL/kg) was applied in 13 normal and 16 VX2bearing rabbits by intravenous bolus injection. Corresponding parameters of the timeintensity curve: time to enhancement (ET) and time to peak intensity (PIT) were measured using low MI contrast grayscale imaging and Washin/Washout time intensity curve software in 8 normal rabbits. ResultsLow MI grayscale imaging clearly delineated the dynamic enhancement of IVC and the hepatic vein during the whole phase. After contrast agent injection, IVC and the hepatic vein were significantly enhanced and the display intensity rapidly increased to a peak level because of reflush of the right atrium. There were significant differences of parameters of the timeintensity curve between IVC and hepatic parenchyma (P＜0.001). The ET and PIT were earlier in IVC than in hepatic parenchyma. After reflush of the right atrium, echogenicity of the surrounding liver tissues increased and the intensity of IVC and the hepatic vein markedly decreased. Then, IVC and the hepatic vein displayed a slight enhancement again because of a small amount of bubbles coming from the liver sinus during the later phase. ConclusionsDynamic contrastenhanced sonography with a low MI level could provide a realtime and continuous enhancement in images of IVC and of the hepatic vein during the whole phase, which may be useful for diagnosis of IVC and hepatic vein diseases.

Key words:  Ultrasonography; Contrast media; Inferior vena cava；Hepatic vein; Rabbits