经门静脉低机械指数灰阶超声造影在肝肿瘤中的应用

Ultrasonographic portography of the hepatic VX2 tumor with low mechanical index gray-scale imaging

目的：应用经门静脉低机械指数灰阶超声造影研究肝恶性肿瘤门静脉供血特点。方法：分别经门静脉主干对12只荷VX2瘤新西兰大白兔快速注射超声造影剂Sono Vue，应用CnTi（contrast tuned imaging）低机械指数实时灰阶造影匹配成像技术，分析22个VX2瘤门静脉供血特点与造影增强效应。结果：注射造影剂后肝实质快速强化并很快达到高峰，而肿瘤一般延迟3～6s后才开始增强。门静脉造影22个肿瘤增强可分4种类型：①弥漫增强型7例，表现为肿瘤弥漫性增强，但其增强效应比周围肝实质的强烈增强弱，仍呈负性显影；②门静脉分支型3例，表现为肿瘤内出现门静脉分支影，造影剂微泡在其内快速流动，肿瘤实质仅轻微增强；③周边增强型5例，表现为肿瘤周边不规则增强，肿瘤边界变得模糊；④无明显增强型7例，表现为肿瘤内无明显强化。结论：经门静脉低机械指数灰阶超声造影可观察肝实质与肿瘤内造影剂的动态增强过程；为病灶的定性诊断及个性化介入治疗提供有价值的信息。

Objective To evaluate the characteristics of portal supply of hepatic tumors by ultrasonographic portography. Methods An in vivo model was studied using SonoVue, and low mechanical index （MI） gray-scale harmonic imaging. SonoVue （0.05 ml） was administrated through catheter placed into the main trunk of portal vein at laparotomy,followed by a 0.5 ml saline flush respectively in twelve rabbits with hepatic VX2 tumor. Results After SonoVue was injected, the liver parenchyma was enhanced and rapidly increased to the peak signal intensity, where the tumors were clearly and easily identified as areas devoid of enhancement that appeared as hypo- or nearly anechoic lesions due to the rapid increase of echogenity in the surrounding liver parenchyma. Three to six seconds after SonoVue injection, the tumors began to be enhanced gradually with an increase of echogenieity. Among 22 tumors, 7 tumors diffusely increased, with the intensity of enhancement weaker than that of the surrounding liver parenchyma. SonoVue was washed out earlier from tumors than from liver parenchyma. Three tumors showed the branches of portal vein. Five tumors showed peripheral contrast enhancement and a central coarse unenhanced hypoechoic area. Seven tumors displayed no actual enhancement. Conclusions Ultrasonographic portography,combined with low MI levels and SonoVue, is a sensitive and safe method to study portal blood supply for liver cancer. It may contribute to improvement of the detectability and diagnostic ability and assist the choice of a therapeutic strategy for treatment of liver cancer.