中文摘要：

目的探讨高分辨率MRI对直肠癌T分期的诊断价值。方法回顾2005年1月至2008年12月245例经病理证实的直肠癌患者，行术前MRI检查。根据直肠癌局部浸润的高分辨率MRI征象做出分期诊断，并与术后病理组织学肿瘤T分期进行对照研究。结果MRIT分期准确率为83．7％（205／245）。MRI和病理T分期的一致性较好（K=0．693，95％CI：0．611-0．776）。97例患者接受术前放疗和（或）化疗，新辅助治疗后MRI分期与病理T分期的一致率为73．2％（71／97，K=0．563，95％CI：0．428-0．698）。直接手术患者148例，MRI分期与病理T分期的一致率为90．5％（134／148，K：0．794，95％CI：0．692-0．896）。肿瘤病理分期与肠管周径侵犯程度中度相关（p=0．619，P〈0．01）。结论高分辨率MRI对于直肠癌T分期有着较高的诊断准确性，有助于制定合理的治疗方案。对于术前接受新辅助放化疗病例在手术前应重新做MRI分期。肠管周径侵犯程度的评价对MRI直肠癌T分期诊断有一定的帮助。

英文摘要：

Objective To assess the correlation of preoperative high-resolution-MRI with histopathologic findings in tumor staging of rectal carcinoma. Methods From January 2005 to December 2008, 245 cases of pathologically confirmed rectal cancer, who received preoperative scan by a 1.5 T high- resolution-MRI were included in this retrospective study. To extracte image signs from high-resolution MRI, and made a diagnosis for tumor staging classification. Assessment for diagnostic accuracy of high-resolution MRI was made with comparison of histopathological classfication. Results The overall diagnostic accuracy of T-stage was 83.7% （205/245）. The consistency coefficient （K） between the MRI and histopathologie T-stage was 0.693 （95% CI：0. 611-0. 776） , which was considered good. For the 97 cases with preoperative chemoradiotherapy, the agreement rate between the post-chemoradiotherapy MRI and histopathologic T-stage was 73.2% （71/97, K = 0.563, 95% CI： 0.428-0. 698） . For the 148 cases without preoperative chemoradiotherapy, the agreement rate between the MRI and histopathologic T-stage was 90. 5% （ 134/148, K = 0. 794, 95% CI： 0. 692-0. 896 ）. The histopathologic T-stage and diameter infringement were in moderate related degree （ p = 0. 619, P 〈 0. 01 ）. Conclusions High-resolution MRI is proved to have a high degree of diagnostic accuracy for T-stage of rectal carcinoma. Preoperative MRI is helpful in treatment planning. Patients undergoing preoperative chemoradiotherapy should receive MRI scan again after neoadjuvant therapy for restaging. The assessment of circumference violation make sense for the accurate diagnosis for tumor staging.