多层螺旋CT评价急性肠系膜缺血严重性的实验研究

Experimental Study of Multi-slice Spiral CT Evaluation of Acute Mesenteric Ischemia Severity

目的:建立犬急性肠系膜缺血(AMI)的动物模型,探讨MSCT表现与缺血时间、缺血程度的相关性,并与病理对照,评价MSCT对AMI的诊断价值。材料和方法:健康成年杂种犬18只,体重15～20kg,雌雄不限。应用Seldinger技术经犬右股动脉穿刺,以无水乙醇栓塞肠系膜上动脉远端的空肠及回肠分支,建立犬AMI模型。将18只AMI模型犬于栓塞术前、术后1～6h行MSCT平扫及双期增强扫描,每隔1h随机处死3只,取缺血段肠标本。结果:18只实验犬均成功建立AMI模型。缺血不同时段的CT表现不同,早期表现为肠系膜水肿、肠腔扩张、肠壁增厚,后期出现腹水、肠壁积气及门静脉积气。术后异常肠壁的增强幅度均小于术前,3～6h组大体和组织学观察可见肠壁缺血的改变。结论:多层螺旋CT可明确诊断肠系膜缺血,且随着缺血时间的延长CT表现逐渐增多,其增强幅度与其缺血时间及缺血程度呈负相关。

Purpose To investigate the association of multi-slice spiral CT（MSCT）appearances and ischemia time as well as ischemia degree through both unenhanced and contrast-enhanced MSCT scans,then to investigate the value of MSCT in diagnosing acute mesenteric ischemia（AMI）by comparing the MSCT findings with pathologic examinations after establishing canine＇s AMI model.Materials and Methods 18 healthy hybrid canines were successfully punctured into the right femoral artery through seldinger＇s technique and injected absolute ethanol into the distal branches of superior mesenteric artery（SMA）for embolization via a 5F Cobra catheter.All experimental canines were underwent both unenhanced MSCT and enhanced CT scans no matter before nor after embolization.Every 3 canines were put to death randly each hour and ischemia bowel biopsies were examined.Results The AMI＇s models were suceessfully established in all 18 canines.The MSCT appearances were not same in different periods.Mesenteric stranding,bowel-wall thickening and luminal dilatation occurred in early periods and ascites,intramural gas and portal venous gas occurred lately.The contrast-enhanced degrees of abnormal bowel walls after embolization were declined than that of preoperation.The canines of three-hour to six-hour ischemia groups developed microscopic and gross changes of bowel ischemia.Conclusion MSCT can make the diagnosis of AMI accurately and the appearances of CT were gradually more variety along with the ischemia time longer.The contrast-enhanced degrees of abnormal bowel walls were negative correlation with ischemia time as well as ischemia degree.