高分辨MRI双重造影结合DWI对直肠癌术前分期的研究

A Study on High-resolution MRI and Double-contrast MRII Combined with DWI in the Preoperative Local Staging of Rectal Cancer

目的:采用高分辨率小FOV双重造影结合DWI扫描技术,探讨磁共振成像(MRI)对直肠癌术前分期的意义。方法:收集2013年1月至2016年1月直肠癌的病例250例,综合所有序列对直肠癌病灶进行术前MRI-TN分期,评估直肠系膜筋膜和环周切缘是否累及,并与手术病理结果进行对照分析。结果:MRI T分期准确率为88.8%(222/250),MRI诊断直肠癌各T分期的准确率、敏感性、特异性、阳性预测值及阴性预测值与术后病理T分期的一致性较好,Kappa值=0.712,P=0.000。N分期准确率为75.6%(189/250),MRI诊断各N分期的准确率、敏感性、特异性、阳性预测值及阴性预测值,与术后病理的一致性为中度一致,Kappa值=0.623,P=0.000。环周切缘准确率为97.6%(58/52)。敏感性100%、特异性97.0%、阳性预测值及阴性预测值分别为89.7%、100%。结论:1薄层、小FOV高分辨率MRI双重造影结合DWI可以多参数、多角度对直肠癌术前T分期做出准确的分期,对N分期做出较准确分期。2 MRI可以对环周切缘有无累及进行准确的预测。3矢状位能准确测量肿瘤下缘距肛缘的距离,为术前评估是否保肛提供直观信息。

Objective： This study aims to analyze the significance of MRI in the preoperative local staging of rectal cancer by high-resolution MRI Imaging and double-contrast MRI combined with diffusion-weighted imaging（DWI） imaging technique. Methods： A total of 250 patients clinically diagnosed with rectal cancer were enrolled into this study from January 2013 to January 2016.MRI-TN preoperative staging was used for rectal cancer lesions, based on all sequences. The mesorectal fascia and circumferential resection margin involvement was evaluated and comparatively analyzed through the pathological results of the operation. Results： The overall diagnostic accuracy of T staging was 88.8%（250/222）. Diagnosis accuracy rate, specificity, sensibility, PPV and NPV of rectal carcinoma T-stage by MRI were consistent with postoperative pathological T staging（kappa = 0.712, P = 0.000）. The overall diagnostic accuracy of N-stage was 75.6%（250/189）. Diagnosis accuracy rate, specificity, sensibility, PPV and NPV of rectal cancer N staging by MRI were moderately consistent with postoperative pathological N-stage（kappa = 0.623, P = 0.000）. The overall diagnostic accuracy of CRM involvement was 97.6%（58/52）. In judging CRM involvement by MRI, accuracy rate was 97.6%, sensibility was 100%, specificity was 97.0%, PPV was 89.7%, and NPV was 100%. Conclusion：（1） high-resolution of thin-section MRI and double-contrast MRI combined with DWI can provide the accurate T staging of preoperative rectal cancer and provide a relatively accurate multi-parameter and multi-angle N staging.（2） MRI can accurately predict CRM involvement.（3） The sagittal view can accurately measure the distance from the lesion edges to the anus, which offer visual information for preoperatively deciding whether to keep the anus or not.