Application Of Magnetic Resonance Imaging In Metastatic Lymph Nodes And Evaluation Of Radiotherapy Of Nasopharyngeal Carcinoma

Objective: To study the value of diffusion-weighted imaging in lymphnodes metastatic of nasopharyngeal carcinoma and analysis the relationship oftumor recurrence with T、N-staging of nasopharyngeal carcinoma.Methods:101patients with newly diagnosed NPC and healthy volunteerswere given MRI routine and DWI scan. ADC Detect values of metastaticlymph nodes in nasopharyngeal carcinoma patients and cervical lymph node inhealthy volunteers and then compare the ADC values of these people. Analyzethe correlation of cancer recurrence and T、N-staging in nasopharyngealcarcinoma. The statistical process of the obtained data were analyzed withSPSS17.0software.Results:1.The pathological diagnosis of101patients were squamous cellcarcinoma in59cases and42cases of other pathological types. There were48patients with cervical lymph node metastasis and33patients withretropharyngeal lymph node metastasis. Measure ADC value of53positivelymph nodes randomly selected and then contrast that with lymph node ofhealthy volunteers.①ADC value of metastatic lymph nodes in patients withnasopharyngeal carcinoma（0.7192±0.0414） was significantly lower thanADC value of health volunteers（0.8758±0.0573）.The statistic results showthat there is significant difference between ADC value of metastatic lymphnodes in nasopharyngeal carcinoma and health volunteers（t=16.139,P＜0.01）. ②The ADC value of metastatic lymph nodes in the short diameter group(≤15mm) was0.6823±0.0252. The ADC value of metastatic lymph nodes inthe long diameter group (＞15mm) was0.7415±0.0321.There is significantdifference between ADC value of metastatic lymph nodes in the two groups（t=-7.025,P<0.01）.③.The statistic results show that there is significantdifference between ADC value of metastatic lymph nodes in the short diametergroup(≤15mm) and in health volunteers（t=-19.985,P<0.01）.2.The distribution of Tumor stage was as follows:29patients belong to T1staging group,30to T2staging group,21to T3staging group, and21to T4staging group.83patients were detected tumor recurrence. The recurrence rateof nasopharyngeal carcinoma was82.2%(83/101). According to the violationextent of the cancer, the patients were divided into two group: the highviolation group and the low violation group. The recurrence rate ofnasopharyngeal carcinoma was75.0%in T1+T2group and97.6%in T3+T4group. The difference of recurrence rate in the two group was statisticallysignificant(χ2=9.299,P=0.002).The recurrence rate of nasopharyngealcarcinoma was significantly different among different T-staging. With theincrease in local invasion of primary tumor(T stage), the recurrence rate afterthe fist radiotherapy increases.3.101patients were divided into two group according toN-staging:N1a+N1b group and N2+N3group.The recurrence rate ofnasopharyngeal carcinoma in N1a+N1b group and N2+N3group was67.7%and64.0%respectively. The difference of recurrence rate in the two groupwas not statistically significant(χ2=0.118,P=0.731).There is no definitivevariation between recurrence rate and N-staging.Conclusion:1.ADC value provides an alternative way to differentiate metastatic lymphnodes of nasopharyngeal carcinoma from normal lymph nodes. 2.There is correlation between the recurrence of primary cancer andT-staging of nasopharyngeal carcinoma. With the increase in local invasion ofprimary tumor(T stage), the recurrence rate after the fist radiotherapy increases.3.There is no definitive variation between recurrence rate and N-staging inprimary tumor. The difference of recurrence rate in N1a+N1b and N2+N3group was not statistically significant.