肠系膜静脉结扎致急性肠缺血的多层螺旋CT研究

目的 探讨MSCT显示肠系膜静脉结扎致急性肠缺血的早期征象及其动态演化规律.方法 12只巴马猪,采用数字表法随机分成3个实验组(术后6、12、18 h组)和1个对照组,每组3只.实验组9只猪剖腹结扎肠系膜上静脉(SMV)主干远端空肠、回肠和回结肠支,分别于术前及术后6、12和18 h采用MSCT行平扫和增强后动脉、静脉和延迟期扫描.对照组3只猪仅剖腹分离暴露SMV,并于上述时间点进行扫描,比较手术前后肠系膜血管、肠道、腹腔形态的动态变化,结果与病理对照.结果 9只实验组猪均显示急性肠缺血病理改变,随时间延长,缺血进行性加重.CTA可准确显示SMV主干、大属支及其远端小分支直至肠壁边缘的直小静脉,显示SMV分支各结扎点.静脉堵塞性肠缺血的早期CTA改变为肠系膜上动脉痉挛、充盈欠佳、显影延迟和延长;SMV显影淡、延迟;肠壁增厚,系膜水肿,腹水,肠壁强化高于正常;随时间推移,出现肠壁变薄,肠腔扩张、积液,系膜水肿,腹水加重,肠壁强化减弱.结论 CTA能清晰显示肠系膜血管解剖、堵塞的静脉、早期肠缺血改变及其动态演化规律,于病变早期可靠地诊断静脉堵塞性肠缺血.

Multi-slice CT evaluation of acute mesenteric ischemia induced by ligation of superior mesenteric vein in a porcine model

Objective To investigate MSCT for detecting the early sign and dynamic evolution of acute mesenteric ischemia (AMI) induced by ligation of superior mesenteric vein (SMV) in experimental porcine model.Methods Twelve pigs were assigned randomly to three experimental groups and one control group with 3 pigs in each group.After laparotomy,SMV was separated and ligated in 9 pigs,and separated without ligation in 3 control pigs.Pre-and postcontrast MSCT with arterial,venous and delay phase scans,and CT angiography (CTA) reconstructions of mesenteric vessels were carried out at preoperation,6,12 and 18 h after ligation.The changes of mesenteric vessels,bowel,abdominal cavity pre-and post-operation,and dynamic evolution were evaluated. The results were compared with those of pathology. Results AMI changes were identified pathologically in all 9 experimental pigs.MSCT angiography clearly delineated main trunk of SMV,peripheral major and minor tributaries up to brushy vasa recta.It correctly identified the location and shape of ligations.The early ischemic findings appeared as follows:the spasm of superior mesenteric artery (SMA) and its major branches which displayed poor filling and delayed and prolonged visualization,poor and delayed opacification of SMV and its tributaries,bowel wall thickness,mesenteric stranding,ascite and pronounced bowel enhancement.With time lapse,thinning bowel wall,dilated bowel with fluid,aggravating edema of mesentery and ascite and poor enhanced bowel were identified.Conclusion CTA can reliably define normal and occluded mesenteric vessels,detect early changes mesenteric ischemia and evolution,and diagnosis venous occlusive AMI.