TY - JOUR T1 - Differentiation of Recurrent Tumor and Posttreatment Changes in Head and Neck Squamous Cell Carcinoma: Application of High b-Value Diffusion-Weighted Imaging JF - American Journal of Neuroradiology JO - Am. J. Neuroradiol. SP - 2343 LP - 2348 DO - 10.3174/ajnr.A3603 VL - 34 IS - 12 AU - I. Hwang AU - S.H. Choi AU - Y.-J. Kim AU - K.G. Kim AU - A.L. Lee AU - T.J. Yun AU - J.-h. Kim AU - C.-H. Sohn Y1 - 2013/12/01 UR - http://www.ajnr.org/content/34/12/2343.abstract N2 - BACKGROUND AND PURPOSE: High b-value DWI has been expected to have an additional diagnostic role and demonstrated some promising results in head and neck cancer. The aim of this study was to evaluate the diagnostic performance of DWI at a high b-value (b=2000 s/mm2) compared with a standard b-value (b=1000 s/mm2) and the ratio of ADC values of high and standard b-values for their ability to differentiate between recurrent tumor and posttreatment changes after the treatment of head and neck squamous cell carcinoma. MATERIALS AND METHODS: A total of 33 patients diagnosed with head and neck squamous cell carcinoma were enrolled in the present study; all had contrast-enhancing lesions on follow-up MR imaging. All patients underwent single-shot echo-planar DWI at b=1000 s/mm2 and b=2000 s/mm2, and corresponding ADC maps were generated (ADC1000 and ADC2000, respectively). The mean ADC1000, ADC2000, and ADCratio (ADCratio = ADC2000/ADC1000 × 100) values were evaluated within a manually placed ROI with contrast-enhanced T1-weighted images as references. For the statistical analysis, we performed a Student t test and multivariate logistic regression. RESULTS: The mean ADC1000 in recurrent tumor was significantly lower than that in posttreatment changes (P < .001), whereas the mean ADC2000 resulted in no significant difference (P = .365). The mean ADCratio was significantly higher in recurrent tumor than that in posttreatment changes (73.5 ± 7.2% vs 56.9 ± 8.8%, respectively; P < .001). Multivariate logistic regression analysis revealed that the ADCratio was the only independently differentiating variable (P = .024). The sensitivity, specificity, and accuracy of ADCratio were 95.0%, 69.2%, and 84.8%, respectively, by use of the optimal cutoff value of 62.6%. CONCLUSIONS: We suggest that the ADCratio calculated from the ADC1000 and ADC2000 is a promising value for the differentiation of recurrent tumor and posttreatment changes in head and neck squamous cell carcinoma. ADC1000ADC value calculated at b=0 and 1000 s/mm2ADC2000ADC value calculated at b=0 and 2000 s/mm2ADCratioratio of ADC2000 over ADC1000HNSCChead and neck squamous cell carcinoma ER -