摘要目的:探讨基于MRI的颈部影像报告和数据系统（NI-RADS）对鼻咽癌腔外局部肿瘤复发（ELRNPC）与治疗后改变（PTC）的鉴别诊断价值。方法:回顾性收集2015年4月至2020年9月中山市人民医院经病理或随访确诊的33例ELRNPC和37例PTC患者。先由2名影像医师独立进行常规MRI的NI-RADS分类，再结合扩散加权成像（DWI）进行NI-RADS分类，3个月后，由其中1名高年资医师再次进行分类。采用Cohen′s Kappa检验评估观察者间、观察者内NI-RADS分类一致性。绘制受试者操作特征性曲线评价NI-RADS分类对ELRNPC与PTC的诊断效能，曲线下面积（AUC）的比较采用DeLong检验。结果:常规MRI、常规MRI结合DWI的NI-RADS分类结果观察者间一致性Kappa值为0.742、0.909，观察者内为0.807、0.934。常规MRI和常规MRI结合DWI的NI-RADS鉴别诊断ELRNPC与PTC的AUC、灵敏度、特异度为0.932（95%CI 0.846~0.978）、87.9%（95%CI 71.8%~96.6%）、94.6%（95%CI 81.8%~99.3%）和0.991（95%CI 0.933~1.000）、93.9%（95%CI 79.8%~99.3%）、97.3%（95%CI 85.8%~99.9%），两者AUC间差异有统计学意义（ Z=2.20， P=0.028）。 结论:基于常规MRI伴或不伴有DWI，NI-RADS鉴别诊断ELRNPC与PTC均具有较高的诊断效能，常规MRI结合DWI的NI-RADS分类一致性和诊断效能更高。

abstractsObjective:To evaluate the diagnostic value of neck imaging reporting and data systems (NI-RADS) based on MRI in extracavity local recurrent nasopharyngeal carcinoma (ELRNPC) and posttreatment changes (PTC).Methods:From April 2015 to September 2020, 33 cases of ELRNPC and 37 cases of PTC confirmed by pathology or follow-up were retrospectively enrolled at Zhongshan City People′s Hospital. Two radiologists independently evaluated the conventional MRI findings using NI-RADS criteria in the first step, then evaluated with conventional MRI and diffusion weighted imaging (DWI) sequences in the second step. All images were re-evaluated by one senior radiologist in the same steps after three months. Inter- and intra-reader agreements were assessed with Cohen′s Kappa test. Receiver operating characteristic curves were generated to assess the diagnostic values of NI-RADS categories between ELRNPC and PTC. The area under the curve (AUC) was compared by Delong test.Results:Inter- and intra-reader agreements of Kappa value were 0.742 and 0.909 for conventional MRI and 0.807 and 0.934 for conventional MRI with DWI. In the differential diagnosis of ELRNPC and PTC, the AUC, sensitivity, and specificity of NI-RADS categories based on conventional MRI were 0.932 (95%CI 0.846-0.978), 87.9% (95%CI 71.8%-96.6%), 94.6% (95%CI 81.8%-99.3%), and of NI-RADS based on conventional MRI with DWI were 0.991 (95%CI 0.933-1.000), 93.9% (95%CI 79.8%-99.3%), 97.3% (95%CI 85.8%-99.9%), respectively. There was a statistical difference between the AUCs of the two categories ( Z=2.20, P=0.028). Conclusions:For both the NI-RADS based on MRI with or without DWI, the differential diagnostic value of ELRNPC and PTC is excellent, while the consistency and diagnostic performance are more substantial when combined with DWI.