The diagnostic role of diffusion-weighted magnetic resonance imaging in hypopharyngeal carcinoma

The aim of the present study was to assess the role of diffusion-weighted magnetic resonance imaging (DWI) and apparent diffusion coefficient (ADC) values in hypopharyngeal carcinoma. A total of 40 hypopharyngeal carcinoma tissues and 15 benign lesion tissues were retrospectively analyzed. DWI, and T1- and T2-weighted magnetic resonance imaging (MRI) was performed. The sensitivity, specificity and accuracy of conventional MRI were 97.5, 66.7, and 89.1%, respectively. The mean ADC value [diffusion sensitive factor (b)=1,000× sec/mm²) for hypopharyngeal carcinomas was (1.0285±0.0328)×10^-3 mm²/sec, which was significantly lower than the mean ADC value for benign lesions [(1.5333±0.1061)×10^-3 mm²/sec; P<0.001]. Receiver operating characteristic (ROC) curve analysis revealed that the area under the curve (AUC) was 0.921 while the optimal threshold for the cut-off point of the ADC was 1.075×10^-3 mm²/sec. The mean ADC value of the metastatic nodes was (0.9184±0.0538)×10^-3 mm²/sec, lower than the mean value for the benign nodes [(1.2538±0.1145)×10^-3 mm²/sec; P=0.005]. Two groups were created according to the mean of the ADC value of hypopharyngeal carcinomas [≤(1.0285±0.0328)×10^-3 mm²/sec vs. >(1.0285±0.0328)×10^-3 mm²/sec]. The 2-year survival rates of the two groups were 55.6 and 100.0%, respectively (P=0.024). ADC values may aid in distinguishing hypopharyngeal carcinomas from benign lesions and differentiating metastatic lymph nodes of hypopharyngeal squamous cell carcinomas from reactive cervical lymph nodes. In conclusion, mean ADC values may be useful prognostic factors in univariate analysis of hypopharyngeal carcinoma.