实验兔钝性肝损伤的CT动态增强表现

Manifestation of dynamic contrast-enhanced CT of hepatic injury in rabbits

目的 探讨CT动态增强扫描在兔钝性肝损伤（rabbit hepatic injury,BHI）模型中的诊断价值.方法 新西兰大白兔40只,采用钢球自由落体对剑突直接撞击,建立兔BHI模型.采用美国通用（GE）公司Hispeed双螺旋CT机行肝脏平扫及增强,注射对比剂开始后8～10 s、35～40 s、120～150 s分别为肝动脉期、门脉期及平衡期.观察增强前后损伤的位置、范围、边界、肝包膜撕裂、有无活动性出血、主要肝静脉有无受累及腹腔积血的CT特征,并与大体解剖情况对比.结果 动态增强扫描显示率明显高于平扫,单一撕裂13只,多发性撕裂伤18只,肝包膜下血肿7处,肝实质内血肿9处,肝包膜裂口17只25处,活动性出血9处,主要肝静脉损伤5处;与大体解剖符合情况分别为13/13（只）,18/18（只）,7/9（处）,9/9（处）,25/30（处）,9/5（处）,5/4（处）.按Moore分级,CT/剖腹探查结果分别为：Ⅰ级5/4只,Ⅱ级15/13只,Ⅲ级9/11只,Ⅳ级6/6只,Ⅴ级1/2只,Ⅵ级0只.结论 动态CT增强扫描尤其静脉期和平衡期对明确有无肝脏损伤及判断损伤程度具有重要的价值.

Objective To analyze the features of dynamic contrast-enhanced CT of blunt hepatic injury in rabbits. Methods The model of blunt hepatic injury was established in 40 New Zealand white rabbits with a steel ball falling down to the xiphoid process of the animals. Plain CT scan and dynamic contrast-enhanced CT scan （Hispeed spiral CT/2i, GE, America） of the liver were performed. Arterial,portal and balanced phases were respectively at 8-10 s, 35-40 s and 120-150 s after initiation of the contrast medium injection. The non-enhanced and enhanced images were compared in aspects of location and range of injury, tear of the liver capsule, active bleeding, involvement of the main hepatic veins and CT features of abdominal hemorrhage, which was further compared with the results of gross anatomy. Results The rate of plain CT scan was obviously lower than that of dynamic contrast-enhanced CT scan,which defined single tear in 13 patients, multiple lacerations in 18, liver subcapsular hematoma in seven,liver hematoma in nine, liver coated gap in 17, active bleeding in nine and main hepatic vein injury in five, with coincidence rates with the results of gross observation for 13/13,18/18,7/9,9/9,25/30,9/5and 5/4 respectively. According to Moore＇ s classification, CT/Laparotomy performed from grade Ⅰ to grade Ⅵ were 5/4 patients at grade Ⅰ , 15/13 at grade Ⅱ, 9/11 at grade, 5/6 at grade Ⅳ, 1/2 at grade Ⅴ, O at grade respectively. Conclusion Dynamic contrast-enhanced CT scan, especially at portal and balanced phases, is of great value for diagnoses of liver injuries and determination of injury severity.