目的 探析鼻咽癌调强放疗前后 MRI影像变化及在疗效评估中的应用价 值。方法 以我院2012年1月～2014年8月 收治50例鼻咽癌患者进行研究，所有患 者均行调强放疗并于治疗前后进行MRI检 查，统计治疗有效率、对比纤维化与复发 患者放疗后MRI曲线斜率。结果 治疗前 T1WI呈等信号、T2WI高信号、DWI图像呈 高信号。治疗后T2WI呈非均匀高信号、 T1WI呈低信号，DWI序列呈信号减低，边 界较治疗前清晰，增强扫描表现为不均匀 强化。放疗治疗有效率92.0%(46/50)，纤 维化组斜率明显低于复发组(P＜0.05)。 结论 MRI检查可准确显示肿瘤范围而勾画 放射治疗靶区，根据肿瘤形态的改变评价 调强放疗效果，并对复发与纤维化进行鉴 别，对鼻咽癌临床疗效及预后评估具有明 显价值，值得推广。

Objective To explore the changes of MRI images before and after intensity modulated radiotherapy for nasopharyngeal carcinoma and the application value in efficacy evaluation. Methods 50 patients with nasopharyngeal carcinoma who were admitted into the hospital during January 2012 to August 2014 were studied. All patients were treated with intensity modulated radiotherapy and received MRI examination before and after the treatment. The treatment effective rate was statistiacally analyzed. The slope of MRI curve was compared between fibrosis and recurrent patients after radiotherapy. Results Before the treatment, uniform signal was on T1WI, high signal on T2WI of and high signal on DWI images. After the treatment, uneven high signal was on T2WI, low signal on T1WI and signal decreasing on DWI sequence. The boundary was clearer than that before the treatment and the enhanced scan showed inhomogeneous enhancement. The effective rate of radiotherapy was 92.0%(46/50). The slope of the fibrosis group was significantly lower than that of the recurrence group and the difference was statistically significant (P ＜0.05). Conclusion The application of MRI in nasopharyngeal carcinoma can be used to accurately display the range of tumor and radiotherapy target region. According to the change of tumor morphology, the effect of intensity modulated radiotherapy is evaluated. Recurrence and fibrosis are differentiated. It is of significant value in the evaluation of clinical curative effect and prognosis of nasopharyngeal carcinoma, which is worthy of promotion.