中文摘要：

目的：探讨磁共振扩散加权成像（DWI）以及表观扩散系数（ADC）值对非小细胞肺癌肺门纵隔淋巴结转移的鉴别诊断价值。方法：收集45例南昌大学第二附属医院肿瘤科收治的经皮穿刺活检或纤维支气管镜检查病理确诊为非小细胞肺癌（NSCLC）的初治患者，对其行术前常规胸部sE序列MRI平扫和纵隔DWI扫描（b值分别为600、800和1000s／mm2），测量并记录不同b值时肺门纵隔淋巴结的ADC值，以术后病理结果作为诊断的金标准，分析非小细胞肺癌肺门纵隔淋巴结的DWI与ADC值特点。结果：45例患者共送检淋巴结791枚，其中在DWI上测得ADC值的淋巴结共计68枚，包括32枚转移性淋巴结和36枚反应增生性淋巴结。最合适的b值为600s／mm2，在此条件下，转移性淋巴结的平均ADC值为（1．73±0．24）×10^-3mm2／s，反应性增生淋巴结的平均ADC值为（2．67±0．16）×10^-3mm2／s，转移性淋巴结组平均ADC值明显小于反应性增生淋巴结组（P〈0．001）。转移性淋巴结不同病理类型间的平均ADC值差异无统计学意义（P〉0．05）。当以平均ADC值〈2．32×10^-3mm2／s为阈值诊断非小细胞性肺癌肺门纵隔淋巴结有无转移时，其准确度、敏感度、特异度、假阳性率、假阴性率、阳性预测值和阴性预测值分别为82％、71％、92％、31％、8％、76％和90％。结论：DWI对NSCLC患者肺门纵隔淋巴结良恶性的鉴别具有较高的诊断价值，是一种快速可行的影像学技术。

英文摘要：

Objectives： This study aims to evaluate the capability and reliability of diffusion-weighted imaging （ DWI ） in differentiating metastatic from non-metastatic mediastinal lymph nodes in patients with non-small cell lung cancer （ NSCLC ）. Methods： Forty-five consecutive patients with pathologically confirmed NSCLC underwent echo-planar diffusion-weighted magnetic resonance imaging of the mediastinum with b-factors of 600, 800, and 1,000 s/mm2. The apparent diffusion coefficient （ ADC ） values of the mediastinal lymph nodes were calculated. The ADC values were correlated with the biopsy results. A value of P 〈 0.05 was considered statistically significant. Results： The mean ADC value of malignant mediastinal lymphadenopathy （ 1.73 mm2/s ± 0.24×10^-3mm2/s ） was significantly lower （ P 〈 0.05 ） than that of benign lymphadenopathy （ 2.67 mm2/s ±0.16 ×10^-3mm2/s ）. A significant difference in the ADC values was observed between metastatic and benign nodes （ P 〈 0.05 ）. However, no significant difference in the ADC values was observed between the metastatic lymph nodes of different pathologies. Given an ADC value of 2.23 ×10^-3mm2/s as the threshold for differentiating malignant mediastinal nodes from the benign nodes, the best results were obtained with an accuracy of 82 %, false negative rate of 31%, negative predictive value of 90 %, and positive predictive value of 76 %. The area under the curve was 0.96. Conclusion： DWI may be a feasible and reliable method to discriminate malignant mediastinal lymph nodes from benign nodes in patients with NSCLC.