Diagnostic accuracy of sonography versus magnetic resonance imaging for primary nasopharyngeal carcinoma.

Objectives: The purpose of this study was to prospectively assess the accuracy of sonography versus magnetic resonance imaging (MRI) for a diagnosis of primary nasopharyngeal carcinoma.

Methods: A total of 150 patients suspected of having nasopharyngeal carcinoma underwent sonography and MRI. A diagnosis was obtained from an endoscopic biopsy that was collected from the suspected tumor or a normal nasopharynx. The diagnostic performance of sonography and MRI for nasopharyngeal carcinoma was evaluated by receiver operating characteristic curve analysis. The sensitivity and specificity of the two imaging methods were compared by the McNemar test.

Results: Nasopharyngeal carcinoma was present in 71 of 150 patients (47.3%) and absent in 79 (52.7%). The sensitivity, specificity, and accuracy of sonography versus MRI for these cases were 90.1%, 84.8%, and 87.3% for sonography and 97.2%, 89.9%, and 93.3% for MRI, respectively. Both sonography and MRI had good diagnostic performance for nasopharyngeal carcinoma, with area under the curve values of 0.958 and 0.987, respectively. There was no significant difference in the rate of tumor detectability between sonography and MRI (P = .12), and the specificities of sonography and MRI were similar (P = .22).

Conclusions: Both sonography and MRI are useful tools for clinical screening of nasopharyngeal carcinoma. However, sonography is less expensive and easier to perform. The results of this study also suggest that nasopharyngeal sonography could be used for the initial investigation of primary cancer in patients suspected of having nasopharyngeal carcinoma.