MRI增强扫描在鼻咽癌放疗近期疗效评估中的应用价值

Value of using contrast-enhanced magnetic resonance imaging for the evaluation of the short-term effects of radiotherapy for nasopharyngeal cancer

目的探讨MRI增强扫描在鼻咽癌根治性放疗前后判断疗效中的应用价值,并用体视觉分区分析法追踪观察鼻咽癌分期是否对放疗具有敏感性。材料与方法回顾性分析经病理检查证实的50例初诊鼻咽癌患者,其中9例侵犯咽旁间隙或/和口咽（T2）,29例侵犯颅底或/和翼内肌（T3）,12例侵犯颅神经或/和海绵窦或/和鼻窦或/和翼外肌（T4）,均行近期放射治疗（1疗程30次,66~70 Gy/次,5次/周,共6周）,前后均行T1WI、T2WI和MRI增强扫描,利用体视觉分区分析法对病灶形态、范围及周围组织侵犯变化情况进行测量对比。上述数据均使用独立样本t检验进行统计学分析。结果与放疗前对比,MRI增强扫描,9例侵犯咽旁间隙或/和口咽,29例侵犯颅底或/和翼内肌,7例侵犯颅神经或/和海绵窦或/和鼻窦或/和翼外肌的肿瘤病灶明显缩小及颈部淋巴结退小,并强化不明显或无强化趋势（P〈0.05）。但5例病理分期为T4肿瘤中4例大小变化不明显及1例增大（P〈0.05）,并且病灶标准化强化强度变化也不明显。结论 MRI增强扫描灵敏显示鼻咽癌放疗前后的变化,对鼻咽癌的疗效评价具有很好的临床应用价值。另外,鼻咽癌放疗疗效与病理分期相关。

Objective： To investigate the value of using contrast-enhanced magnetic resonance imaging（MRI） for effi cient evaluation before and after radical radiotherapy for nasopharyngeal cancer, and to assess whether the use of visual partitioning analysis for tracking and observing nasopharyngeal cancer staging is sensitive to radiotherapy. Materials and Methods： In total, 50 patients who were preliminarily diagnosed with nasopharyngeal cancer through pathological examinations were retrospectively analyzed, including 9 cases with stage T2, 29 cases with T3, and 12 cases with T4. All cases underwent short-term radiotherapy; T1 weighted imaging, T2 weighted imaging, and contrast-enhanced MRI were performed before and after radiotherapy. visual partitioning analysis was used to comparatively measure the variation in morphology and range of foci, as well as the involvement of surrounding tissues. All the above mentioned data were statistically analyzed using independent sample t-tests. Results： Compared to the conditions before radiotherapy, the tumor foci of 9 cases with parapharyngeal space and/or oropharynx involvement, 29 cases with skull base and/or medial pterygoid involvement, and 7 cases with cranial nerve and/or cavernous sinus and/or paranasal sinus and/or lateral pterygoid involvement showed signifi cant shrinkage or reduction in the size of their cervical lymph nodes, along with nonapparent enhancement or no trend in enhancement（P〈0.05）. However, among 5 T4 cases, the tumor size non-signifi cantly changed in 4 cases and increased in 1 case（P〈0.05）; moreover, the intensities of the standardized enhancement of foci did not signifi cantly change. Conclusion： The changes in nasopharyngeal cancer before and after radiotherapy can be sensitively determined through contrast-enhanced MRI, which may thus have good clinical applicability in the effective evaluation of nasopharyngeal cancer. Moreover, the effi cacy of radiotherapy fornasopharyngeal cancer may be associated with the pathological staging.