中文摘要：

目的 探讨3.0T MRI在直肠癌术前评估中的应用价值.方法 对41例经病理活检证实为直肠癌的患者进行常规MRI、高分辨MRI及扩散加权成像（DWI）扫描,测量肿瘤最下缘离肛缘的距离及累及环周百分比,评估肿瘤的TN分期、环周切缘（CRM）、系膜血管受侵（EMVI）的状态,与肠镜和手术结果比较.结果 MRI对判断肿瘤下缘距肛缘的距离具有很好的预测价值（P〉0.05）;T1~T2期、T3期肿瘤累及环周百分比的平均值分别是61%、83%（P〉0.05）;T、N分期诊断的总准确率分别为80.5%、75.6%,与病理诊断的一致性较好（Kappa值=0.564、0.634）;CRM、EMVI诊断的总准确性分别是90.2%、73.2%,与病理诊断的一致性分别是较好、中度一致（Kappa值=0.765、0.461）.

英文摘要：

Objective To probe the value of 3.0T MRI in the preoperative assessment of rectal carcinoma.Methods The study recruited 41 patients who were confirmed by biopsy of rectal carcinoma and underwent conventional MRI, high-resolution MRI and diffusion weighted imaging（DWI）, the distance from the inferior part of tumor to transitional skin and the percentage of circumferential invasion were measured, the tumor＆#39;s T staging, N staging,and the status of circumferential resection margin（CRM） and extramural vascular invasion（EMVI） were assessed.MRI findings were compared with endoscope and postoperative pathological results.Results MRI could accurately show the distance from the inferior part of tumor to transitional skin（P〉0.05）;The mean percentage of circumferential invasion for the tumor with T1-T2 and T3 were 61%,83% respectively （P〉0.05）;The total accuracy of T,N staging diagnose were 80.5%,75.6% respectively, which had a better consistent with pathological T,N staging（Kappa=0.564,0.634）;The total accuracy of CRM and EMVI diagnose were 90.2%,73.2% respectively,which had a better or moderate consistent with pathological diagnose（Kappa=0.765,0.461）.Conclusion 3.0T MRI has the unique application in the preoperative assessment of rectal carcinoma, which can provide more comprehensive information for clinic.