磁共振成像对直肠癌分期和侧切缘受累的预测价值

目的 评估磁共振成像（MRI）预测直肠癌分期和侧切缘受累的准确程度。方法术前活检病理证实的直肠癌53例,用高分辨率MRI评估肿瘤（T）、系膜淋巴结转移（N）和侧切缘（CRM）,所有病例均行全直肠系膜切除术,采用连续病理切片法观察手术标本,对照术前MRI和术后病理结果,评估MRI能否准确预测直肠癌T、N、CRM。结果MRI正确T分期41例,错误12例,其中4例T1-12期报告为仍期,8例仍期报告为T1-12期,T分期的总准确率为77．4％（41／53）,其中T1～12期的预测准确率为83．3％（20／24）,仍期的准确率为68．0％（17／25）,T4期的准确率为100％（4／4）,MRI可以对T分期进行一般预测,但准确度不高（Kappa值为0．602,P〈0．001）。MRI对直肠系膜淋巴结正确分期37例,错误分期16例,其中高估10例,低估6例,准确率为69,8％（37／53）,灵敏度为75％（18／24）,特异度为65．5％（19／29）,MRI不能对系膜淋巴结做出准确预测（Kappa值为0．399,P=0．003）。MRI正确预测CRM51例,错误2例,其中高估1例,低估1例,准确率为96．2％（51／53）,灵敏度为80％（1／5）,特异度为97．9％（47／48）。MRI可以准确预测CRM是否受累（Kappa值为0．779,P〈0．001）。结论术前MRI不能准确预测直肠癌T、N分期,但可以可靠地预测CRM是否受累。

Accuracy of preoperative magnetic resonance imaging in prediction of pathological stage and circumferential resection margin in rectal cancer

Objective To evaluate the accuracy of preoperative magnetic resonance imaging (MRI) in prediction of pathological staging and involvement of circumferential resection margin (CRM) in rectal cancer.Methods Fifty-three patients undergoing total mesorectal excision for biopsy-proven rectal cancer were assessed prospectively using high-resolution MRI for tumour (T) and mesorectal nodal (N) staging as well as CRM status using the depth of tumour spread, tumour node metastasis and CRM involvement. Preoperative MRI assessment of these prognostic factors was compared with the histopathological findings in carefully matched whole-mount sections of the specimen.Results MRI correctly staged the tumor in 41 patients, understaged in 8, and overstaged in 4. The accuracy of T stage was 77.4%(41/53).There was ageneric correlation between pathologic and MRI tumor staging (Kappa=0.602,P<0.001). Node status was correctly staged in 37 patients, overstaged in 10, and understaged in 6. The accuracy of node staging was 69.8%(37/53), sensitivity was 75%(18/24), and specificity was 65.5%(19/29). The correlation between pathologic and MRI node staging was poor (Kappa=0.399, P=0.003). The CRM status was correctly reported in 51 patients, overstaged in 1, and understaged in 1. The accuracy of CRM status was 96.2%(51/53),sensitivity was 80%(1/5), and specificity was 97.9%(47/48). There was a good correlation between pathologic and MRI CRM involvement (Kappa=0.779,P<0.001). Conclusion Preoperative MRI provides poor predictive data as to subsequent pathologic tumor and mesorectal node stage, but does produce reliable prediction of clear CRM.