The diagnostic value of 1.5T diffusion-weighted MR imaging for small metastatic cervical lymph nodes of nasopharyngeal carcinoma / 实用放射学杂志

ABSTRACT

Objective To study the diagnostic value of 1.5T diffusion-weighted magnetic resonance imaging for small metastatic cervical lymph nodes of nasopharyngeal carcinoma(NPC),and to explore the optimal diagnostic threshold value of apparent diffusion coefficient(ADC)in small metastatic cervical lymph nodes of NPC.Methods 40 patients with histopathologically confirmed NPC were underwent conventional,enhanced and DWI MR.The mean ADC value of large metastatic cervical lymph nodes group,small metastatic cervical lymph nodes group and benign lymph nodes group were measured respectively.Statistical analysis was done by using the SPSS 1 6.0 program software.The receiver operating characteristic (ROC)curve was performed to obtain the ADC thresh-old value of small metastatic cervical lymph nodes and the diagnostic efficacy.Results The mean ADC value of large metastatic cer-vical lymph nodes group was (0.74±0.1 1)×10 -3 mm2/s,which was not significantly different from that in small metastatic cervical lymph nodes group(0.75±0.13)×10 -3 mm2/s,P >0.05.The mean ADC value in benign lymph nodes group was (1.05± 0.18)× 10 -3 mm2/s,which was significantly higher than that in large metastatic cervical lymph nodes group and small metastatic cervical lymph nodes group(P <0.05 ).Using a threshold ADC value of 0.908 × 10 -3 mm2/s for differentiating small metastatic cervical lymph nodes from benign lymph nodes,a sensitivity of 83.2% and specificity of 90.9% were obtained,the area under the ROC curve was 0.92.Conclusion DWI is helpful in the diagnosis of small metastatic cervical lymph nodes of NPC.