目的 探讨1.0T MRI与64层MSCT 在中低位直肠癌术前T分期诊断价值。方 法 收集我院93例经手术病理证实中低位 直肠癌及肿瘤分期患者的临床资料，根 据术前诊断方式分为MRI组与MSCT组，比 较两组术前诊断结果及T分期，并与术 后病理结果比较，评估两者诊断价值。 结果 MSCT各种分期总准确率为65.1％ (28/43)，显著低于MRI检查的总准确率 88.0％(44/50)(P<0.05)；MSCT诊断为 T1-2的灵敏度、准确率依次为64.3％、 86.0％，Kappa为0.629，T3诊断效能依 次是62.5％、86.0％、0.539，T3诊断 效能依次是66.7％、88.4％、0.634。 1.0T MRI T1-2诊断效能依次是80.0％、 86.0％、0.706，T3诊断效能依次是 86.2％、90.0％、0.799，T4诊断效能依 次是75.0％、96.0％、0.728。结论 1.0T MRI与64层MSCT均可用于中低位直肠癌术 前T分期，两者诊断价值相当，但MRI诊 断效能稍高于MSCT，尤其是区分T2、T3 期肿瘤。

Objective To evaluate the value of 1.0T MRI and 64 slice MSCT in preoperative T staging of middle and low rectal cancer. Methods The clinical data of 93 patients with pathologically confirmed middle and low rectal cancer were collected. They were divided into MRI group and MSCT group according to the preoperative diagnostic method.Results of preoperative diagnosis and T staging were compared between the two groups, and the results were compared with postoperative pathological results. The diagnostic value of the two methods was evaluated. Results The total accuracy of MSCT for different stages was significantly lower than that of MRI [65.1% (28/43) vs 88.0% (44/50)] (P<0.05). The sensitivity, accuracy and Kappa value of MSCT diagnosis for T1-2 were 64.3%, 86.0% and 0.629, respectively. The diagnostic efficiencies of T3 were 62.5%, 86.0% and 0.539, respectively, while the diagnostic efficiencies of T4 were 66.7%, 88.4% and 0.634, respectively. The diagnostic efficiencies of 1.0T MRI for T1-2 were 80.0%, 86.0% and 0.706, respectively. The diagnostic efficiencies of T3 were 86.2%, 90.0% and 0.799, respectively, while the diagnostic efficiencies of T4 were 75.0%, 96.0% and 0.728, respectively. Conclusion Both of 1.0T MRI and 64 slice MSCT can be used for preoperative T staging of middle and low rectal cancer. Their diagnostic value is similar, but the diagnostic efficiency of MRI is slightly higher than that of MSCT, especially in differential diagnosis of tumors at stage T2 and T3.