目的 探讨3.0T高分辨MRI对直 肠癌术前精细分期(T分期、N分期，环周 切缘)评估的准确性，为直肠癌的个体化 治疗提供准确的影像学依据。方法 回顾 性分析109例经病理活检确诊的直肠癌患 者。MRI评估肿瘤的大小和肿瘤邻近的结 构，评估T分期、N分期、CRM的情况， 与手术后病理结果对照。结果 在109例 患者中，MRI对直肠系膜和直肠系膜筋 膜显示清晰，能够显示腹膜返折，对T 分期的评估，MRI正确分期102例，总准 确性为93.58%(102/109)。MRI错误分期7 例，包括过低分期3例，过高分期4例。 MRI和病理对T分期的一致性检验，Kappa 值=0.873，P=0.000，显示两种诊断方 法具有较高一致性。对N分期的评估， MRI正确分期92例，N分期总的准确性为 84.40%(92/109)，11例过高分期，6例过 低分期。对环周切缘的评估，MRI评估CRM 受累10例，未受累99例。和DFS相符合率 为94.50%(103/109)。结论 3.0T高分辨 MRI能够清晰显示直肠系膜和直肠系膜筋 膜的结构，对直肠癌术前分期的准确性较 好，MRI能够为直肠癌的个体化治疗提供 准确的影像学依据。

Objective To investigate the 3.0T high-resolution MRI before rectal cancer's preoperative staging of fine (TN staging, circumferential margin) to evaluate the accuracy, which would provide an accurate imaging basis for individualized treatment of rectal cancer. Methods A retrospective analysis of 109 cases was confirmed by the biopsy of patients with rectal cancer. The assessment of tumor size and nearby structures was made to analyze the T and N stage, CRM circumferential margin on MRI data, and postoperative pathologic results. Results MRI for mesorectum and mesorectal fascia clearly displayed peritoneal assessment of T staging, and MRI correctly staged 102 cases, among the 109 patients. The total accuracy was 93.58% (102/109). 3 cases were at low stages, and 4 patients were at high stages. For consistency test results of T MRI and pathological staging, Kappa value=0.873 and P=0.000, which suggests that the two diagnostic methods have a high consistency. MRI identified 92 cases at the correct stage, N stage, with an overall accuracy of 84.40% (92/109), as well as 11 cases at a high stage, and 6 cases at a low stage. 10 cases were involved in assessment of the CRM and MRI assessment of CRM involvement, while 99 cases were not involved. Consistency of DFS was 94.50% (103/109). Conclusion High-resolution MRI can clearly show mesorectum and mesorectal fascia structure before rectal cancer preoperative staging showed a good accuracy. MRI can provide accurate imaging basis for individualized treatment of rectal cancer.