中文摘要：

目的 探讨MRI扩散加权成像（DWI）对鼻咽癌（NPC）T分期的应用价值.方法 对36例经病理证实的NPC初诊患者及36例健康志愿者行鼻咽部DWI扫描、常规MRI平扫及增强扫描,分别测量和统计分析NPC原发灶、受累肌肉、受累斜坡及健康人相应结构的ADC值及其差异;采用ROC曲线获取前述瘤灶的ADC诊断阈值;以放疗后6个月的MRI随访资料为依据,比较DWI＋平扫T2WI＋增强T1WI与平扫T2WI＋增强T1WI 2种组合方法对NPC初诊患者T分期的准确性.结果 ①NPC原发灶区及受累肌肉的ADC值均数低于正常组织,而受累斜坡的ADC值均数高于正常斜坡,且差异均有统计学意义（P〈0.05）;②NPC原发灶、受累肌肉及受累斜坡的ADC诊断阈值分别为0.845×10^-3 mm^2/s、0.861×10^-3 mm^2/s及0.556×10^-3 mm^2/s,各阈值的诊断敏感性分别为94.3%、86.7%及100.0%,特异性分别为85.7%、66.7%及64.3%.③DWI＋平扫T2WI＋增强T1WI较平扫T2WI＋增强T1WI对NPC T分期诊断价值更高.结论 DWI能很好地显示NPC原发瘤及其邻近受累结构,对NPC T分期评估具有较高应用价值.

英文摘要：

Objective To prospectively evaluate the potency of diffusion weighted（DW） magnetic resonance （MR） imaging applied for the T stage of nasopharyngeal cancer. Methods The study included 36 cases of nasopharyngeal cancer patients and 36 healthy volunteers who underwent nasopharynx DW imaging. Apparent diffusion coefficients （ADCs） were measured on primary site of nasopharyngeal cancer, involvement muscle, clivus, and the corresponding tissue of healthy volunteers, respectively. Receiver operating characteristic （ROC） curves analyses were conducted to evaluate the utility of ADC for diagnosis of involved structures. Addition of DWI to fused plain T2 WI and contrast material-enhanced {CE） T1WI set, fused plain T2 WI and CE-T1WI set were separately rated. Results ①The mean ADCs for pr!mary site and involved muscle of nasopharyngeal cancer were significantly lower than those of normal tissue, while the mean ADC value of the involved clivus was higher than that of normal clivus （P〈0.05）. ②The ADC threshold of the nasopharyngeal cancer primary site, involvement muscle and clivus were 0. 845 × 10^-3 mm^2/s, 0. 861 × 10^-3 mm^2/s and 0. 556×10^-3 mm^2/s, the threshold of diagnostic sensitivity were 94.3%, 86.7%, 100.0%, specificity were 85.7%, 66.7%, 64.3%, respectively, The overall characterization accuracy in staging of the addition of DWI to fused plain T2WI and CE-T1 WI set was higher than the fused plain T2 WI and CE-T1WI. The statistical difference was significance between them. Conclusion DW imaging provides useful information for evaluating the T stage of nasopharyngeal cancer.