Study Of Diffusion-weighted Magnetic Resonance Imaging For Cervicallymph Node Metastases In Patients With Oral Squamous Cell Carcinoma

Objective:To evaluate the diagnostic accuracy and clinical value of diffusion-weighted magnetic resonance imaging(MR-DWI) in differentiating metastases and reactive hyperplasia cervical lymph nodes in patients with oral squamous cell carcinoma(OSCC).Materials and Methods:All information of OSCC Patients in Shandong Provincial Hospital from September2009to December2011were carefully checked,142OSCC patients who had undergone neck dissection through area I to V were retrospectively analyzed and well categorized. According to pathologic diagnosis after cervical lymphadenectomy which served as the gold standard, The CT diagnostic specificity, sensitivity and accuracy for OSCC cervical lymph nodes metastases were studied. As main imaging feature of metastases and reactive hyperplasia cervical lymph nodes in MR-DWI and ADC-image were observed, Apparent diffusion coefficients(ADC) of the two groups were measured and Receiver operating characteristic curve (ROC curve) was fitted by ADC levels. The MR-DWI diagnostic specificity, sensitivity and accuracy for OSCC metastatic cervical lymph nodes were calculated according to the ROC curve analysis. Diagnostic results of These two imaging inspection methods for OSCC cervical lymph nodes metastases were compared and statistically analyzed.Results:Among these142patients, Post-surgery pathologic examination revealed69patients with OSCC cervical lymph nodes metastases, metastatic rate was48.6%. The CT (91patients) diagnostic sensitivity, specificity, accuracy, positive likelihood ratio, negative likelihood ratio for OSCC metastatic lymph nodes were76.2%、63.3%、69.2%、2.07、0.38. When b=800mm2/s, the images of MR-DWI were of high quality and accuracy. The average ADC value of metastases cervical lymph nodes[702.2×10-6mm2/s] was significantly lower than that of reactive hyperplasia ones[1036.6×10-6mm2/s](p<0.0001), The maximum ADC value of metastases cervical lymph nodes[1079.9X10"6mm2/s] was significantly lower than that of reactive hyperplasia ones[1489.6×10-6mm2/s](p<0.0001), The minimum ADC value between metastases cervical lymph nodes[345.3×10-6mm2/s] and reactive hyperplasia ones [471.7×10-6mm2/s] showed no statistical significance(p=0.097). Analysis of ROC curve fitted by average ADC levels showed the best threshold ADC value was0.887×10-3mm2/s, with the highest MR-DWI diagnostic specificity, sensitivity and accuracy for OSCC metastatic cervical lymph nodes, Area under ROC curve was0.89. Correlation between MR-DWI/CT diagnosis and pathologic diagnosis were analyzed by Chi-square test, Results showed that a good correlation existed between MR-DWI diagnosis of OSCC cervical lymph node metastases and pathologic examination results(Po=0.850, Kappa:0.694, P<0.005) while a low correlation existed between CT diagnosis of OSCC cervical lymph node metastases and pathologic examination results(Po=0.692, Kappa:0.389, P<0.005).Conclusion:The best threshold ADC value for differentiating metastases cervical lymph nodes and reactive hyperplasia cervical lymph nodes in OSCC patients can be obtained by ROC curve analysis fitted by average ADC level. Diagnostic results of MR-DWI are superior to that of CT examination in ascertaining OSCC cervical lymph node metastases. MR-DWI as a new method to OSCC metastatic cervical lymph nodes imaging may provide reliable information in clinical treatment and prognosis and significant clinical value.