中文摘要：

目的评价MRI判断胰腺癌胰周血管侵犯程度的价值,探讨MRI预测胰腺癌可切除性的最佳界点。方法搜集经手术病理证实的胰腺癌患者41例,均行MRI平扫及增强扫描,37例加做冠状位增强磁共振血管造影（MRA）。术前根据MRI表现,判断胰周血管侵犯情况,按照肿瘤对周围血管侵犯程度的不同,采用1级、2a级、2b级、3a级、3b级和4级进行评价,统计各分级血管的条数,并与手术结果对照。计算以2级和2a级作为可切除判断标准的敏感性、特异性、阳性预测值、阴性预测值和准确率应用受试者工作特性曲线（ROC）确定MRI预测胰腺癌可切除性的最佳界点。结果41例患者中,切除22例,其中20例为根治性切除,2例为姑息性切除。与手术结果对照,MRI共误诊7条血管,其中动脉3条,静脉4条。以1级、2a级、2b级、3a级和3b级作为可切除的标准,判断肿块不可切除的敏感性分别为78.3%、84.8%、67.4%、56.5%和47.8%。ROC曲线显示,以2a级作为MRI预测胰腺癌可切除的最佳界点。结论胰周血管侵犯2a级可作为MRI预测胰腺癌可切除的最佳界点。

英文摘要：

Objective To investigate the role of MRI in evaluating the peripancreatic vessel invasion and resectability of pancreatic carcinoma based on the comparison of MRI image with surgical exploration, and try to establish the criteria for assessment of the sensitivity, specificity and accuracy of resectability. Methods Forty-one pancreatic carcinoma patients confirmed by pathology received preoperative plain and contrast enhanced MRI scan, and 37 of them had additional coronal MRA scan. Peripancreatic vessel invasion was preoperatively assessed based on MRI features, and the vessel invasion degree from the uninvolved to the severely involved was divided into 6 grades represented by 1,2a, 2b, 3a, 3b and 4,respectively. Compared with the findings during the surgery, the sensitivity and specificity of each vessel invasion grade were studied and the receiver operator characteristic curve （ROC） was drawn. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of resectability evaluation based on 2 and 2a degree were calculated respectively. The resectability of involved arteries and veins of grade 2 were also analyzed. Results Of the 41 patients, 22 had resectable tumor, with 20 curative resection and 2 palliative. Compared with the findings during surgery, seven vessels including three arteries and four veins were not correctly interpreted by MRI. If grade 1,2a,2b,3a and 3b was used as the resectable standard,respectively, the sensitivity to predict the unresectbility was 78.3%, 84.8%, 67.4%, 56.5% and 47.8%, respectively. Receiver operator characteristic curve demonstrated that grade 2a was the optimal critical point. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of grade 2a in predicting the unresectbility were 84.8%, 98.5%, 92.9%, 96. 6% and 95.9%. Condtmion Our data showed that grade 2a （tumor involvement 〈 2 cm long and 〈 1/2 circumference of the vessel） may be more sensitive and accurate in predicting the resectabi