高分辨MRI对直肠癌T分期和环周切缘的评估

目的 探讨体外相位阵列线圈高分辨MRI对直肠癌术前T分期和环周切缘判定的价值. 资料与方法 原发性直肠癌患者30例和术后离体直肠癌标本10例,全部行体外相位阵列线圈高分辨MRI检查,将影像学所见与手术病理对照观察. 结果 高分辨MRI对直肠癌T分期判定的整体准确度为86.7%(26/30),对T1～2期诊断的敏感度和特异度分别为66.7%(6/9)和95.2%(20/21),对T3期诊断的敏感度和特异度分别为100.0%(15/15)和73.3%(11/15),对T4期诊断的敏感度和特异度分别为83.3%(5/6)和87.5%(21/24).高分辨MRI对环周切缘判定的敏感度为92.3%(12/13),特异度为82.2%(15/17),准确度为90.0%(3/30). 结论 体外相位阵列线圈高分辨MRI技术可较准确地显示直肠癌的T分期,识别癌结节在直肠系膜内的沉积并预测环周切缘的受累与否,有助于术前选择放、化疗和计划手术方案以确保对病灶的完整切除,降低复发率.

Accuracy of High-resolution Magnetic Resonance Imaging in Predicting Tumor Staging and Circumferential Resection Margin of Rectal Carcinoma

Objective To assess the value of high resolution magnectic resnonance imaging in predicting T stage and resection margin involvement of primary rectal carcinoma befor operatiion. Materials and Methods 30 patients of primary rectal carcinoma were preoperatively assessed by 1.5 T MRI with a phased array coil. 10 resected rectal carcinoma specimens were postoperatively examined using the same high resolution technique. MRI compared with histological results were used to assess the resection specimens. Results The high resolution MRI tumor T-staging agreed with the histological stage in 26(86.7%) of 30 patients and in 10(100%) resected rectal specimens. The MRI sensitivity and specificity was 66.7%(6 of 9) and 95.2%(20 of 21) for pT1-2 lesions, 100.0%(15 of 15) and 73.3%(11 of 15) for pT3 stage lesions, 83.3%(5 of 6) and 87.5%(21 of 24) for pT4 stage tumors. In the assessment of circumferential resection margin, high-resolution MRI had a sensitivity of 92.3%(12/13),a specificity of 82.2%(15/17), and an accuracy of 90.0%(3/30). Conclusion Preoperative high-resolution MRI imaging with a phased-array coil is an accurate imaging tool to evaluate T staging of rectal carcinoma and to help identify whether a tumor deposit or not in the mesorectum, and to predict the involvement of CRM. This technique is helpful in preoperatively selecting the patients who will perform chemotherapy and radiotherapy and planning the surgery promramme to make sure a complete removal of the lateral spread of the tumor and reduce local recurrence rates.