目的探讨3.0T MRI对直肠癌术 前局部亚分期诊断的价值。方法 前瞻性 对33例直肠癌患者检查，进行TN亚分期诊 断，针对≥T3分期病例将肠壁外脉管侵 犯EMVI(Extramural Vascular Invasion) 作为独立因素分析评估，并与临床手 术病理结果对照分析。结果 MRI对T亚 分期总诊断准确率为81.8%(27/33）， T1～T4a期准确率分别为，100%、93.9%、 90.9%、97.0%、90.9%、97.0%、93.9%， 与手术病理学 T分期间一致性检验较好 (Kappa=0.773,P＜0.001）。MRI对N亚分 期总的诊断准确率为 69.7％(23/33)， N0～N2b分期准确率分别为87.9%、 90.9%、81.8%、97.0%、87.9%、93.9%， 与手术病理 N 分期间一致性检验较好 （Kappa=0.619,P＜0.001）。MRI对EMVI 评估，总诊断准确率85.7％（24/28）， E0～E2组准确率分别为89.3%、85.7%、 96.4%，与手术病理间一致性检验较好 (Kappa=0.747,P＜0.001）。结论 MRI在 直肠癌术前TN亚分期诊断中有较高价值， ≥T3期病例将EMVI作为单独因素评估，准 确率较高，有助于完善、细化局部分期。

Objective To evaluate the value of MRI in preoperative sub staging diagnosis of rectal cancer. Methods The selection of 33 cases of rectal cancer, preoperative MRI examination by 3.0T, do TN sub staging, and do the assessment of EMVI(Extramural Vascular Invasion), as a reference for clinical treatments, and contrast with the results of pathological staging operation, make statistic analysis. Results The total accuracy of MRI T sub staging was 81.8% (27/33), The accuracy of MRI T1～T4a staging diagnosis were 100%、93.9%、90.9%、97.0%、90.9%、97.0%、93.9%, MRI for T sub stage was approximately consistent with pathological T stage (Kappa =0.773, P<0.001). The total accuracy rate of MRI N sub staging is 69.7% (23/33), The accuracy rate of N0～N2b staging were 87.9%、90.9%、81.8%、97.0%、87.9%、93.9%, That was approximately consistent with pathological N staging (Kappa =0.619, P<0.001). The total accuracy of EMVI diagnosis was 89.3% (25/28), The accuracy of MRI E0～E2 staging diagnosis were 89.3%、85.7%、96.4%, That was approximately consistent with pathological shows (Kappa=0.747, P<0.001). Conclusion MRI has high value in the preoperative TN sub staging of Rectal cancer, and EMVI as an individual factors considered, MRI has high value in assessment of EMVI, Help to improve the refinement phase, partial evaluation factors.