肝静脉及下腔静脉灰阶超声造影的实验研究

目的应用低机械指数灰阶超声造影研究肝静脉和肝段下腔静脉的动态增强变化规律及其诊断价值。方法分别经耳缘静脉对13只正常和16只荷VX2瘤新西兰大白兔团注超声造影剂SonoVueTM（0.1?mL/kg），应用CnTi(contrast tuned imaging)低机械指数实时造影匹配成像技术，动态观察兔肝静脉和肝段下腔静脉造影增强效应，并应用声学定量时间强度曲线分析(Wash in/Wash out)软件，定量分析8只正常兔下腔静脉造影增强效果。结果在所有造影过程中，肝段下腔静脉和第二肝门处肝静脉内造影剂均随时间延长呈动态增强。在早期从右心房反流来的造影剂，增强明显，是其增强的主要来源，与周围肝组织灰阶对比显著，是观察肝段下腔静脉和肝静脉病变的最佳时期。其开始增强时间和峰值时间均明显提前于肝实质，分别是6.4?s和13.5?s，与肝实质相比，两者差异具有统计学意义（P＜0.001）。随后造影剂逐渐退出，而肝实质逐渐增强，此时下腔静脉和肝静脉增强不明显。后期少量来源于经肝循环的造影剂进入下腔静脉及肝静脉，但增强效果轻微，与周围肝实质灰阶差别不明显，对下腔静脉和肝静脉疾病诊断意义不大。结论低机械指数灰阶超声造影技术能很好的对下腔静脉和肝静脉进行造影，对其疾病有一定的诊断意义。

Low mechanical index gray-scale contrast enhancement in rabbit hepatic vein and inferior vena cava

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.