Preliminary studies of differences in detecting cervical lymph node metastasis of nasopharyngeal carcinoma using CT,MRI and PET-CT

Objective To compare the differences in diagnosis of cervical lymph node metastasis of nasopharyngeal carcinoma among CT,MRI and PET-CT and to explore the value of using 18FDG-PET-CT detection for nasopharyngeal carcinoma(NPC).Methods 68 cases of squamous cell carcinoma of NPC were enrolled in the study.Before treatment,CT,MRI and 18FDG-PET-CT scanning were performed.Results Among 68 cases,positive detection rates of retropharyngeal lymph node metastasis were 26.47%(18/68),61.76%(42/68)and 29.41%(20/68).There had statistical significance among CT,MRI and PET-CT(χ2 =10.940,P=0.004),between MRI and CT(χ2 =8.589,P=0.003) and between MRI and PET-CT(χ2 =7.173,P=0.007).Positive detection rates of cervical lymph node metastasis were 61.76%(42/68),61.76%(42/68)and 55.88%(38/68)based on CT,MRI and PET-CT respectively.There had no statistical significance among CT,MRI and PET-CT(χ2=0.326,P=0.849).PET-CT was superior than MRI and CT in detecting the cervical lymph node metastasis which minimum diameter 1 cm.Conclusion MRI has obvious advantage in detecting retropharyngeal lymph node metastasis of nasopharyngeal carcinoma compared to CT and PET-CT.PET-CT has no advantage in detecting cervical lymph node metastasis of nasopharyngeal carcinoma compared to CT and MRI.PET-CT has a remarkable advantage in detecting cervical lymph node metastasis which minimum diameter 1 cm.