Comparison of sonography and CT for differentiating benign from malignant cervical lymph nodes in patients with squamous cell carcinoma of the head and neck

Abstract

Objective: We compared the ability of sonography and CT to differentiate benign from malignant cervical lymph nodes in patients with squamous cell carcinoma of the head and neck.

Materials and methods: We analyzed 209 cervical nodes (102 metastatic and 107 nonmetastatic) from 62 patients with head and neck cancer. These nodes were topographically correlated by node between images and surgical specimens, and accordingly between sonography and CT.

Results: The area under the receiver operating characteristic curve (A(z) value) for the overall impressions of metastatic or nonmetastatic nodes was significantly greater for sonography (power Doppler sonography plus gray-scale sonography, 0.97 +/- 0.005; gray-scale sonography, 0.95 +/- 0.004) than for CT (0.87 +/- 0.018). Receiver operating characteristic curve analysis also showed that the greater ability of sonography to depict the internal architecture of the nodes (A(z) value, 0.96 +/- 0.006) compared with CT (A(z) value, 0.81 +/- 0.027) significantly contributed to the better performance of sonography compared with CT in diagnosing metastatic nodes in the neck. On the other hand, size criterion (the short-axis diameter) was equally predictive in sonography and CT. The greater contributions of internal architectures relative to the size criterion of the node in the sonographic assessment for metastatic nodes were further evidenced by the findings that sonography provided higher sensitivity and specificity than CT did, whereas the cutoff points for the short-axis diameter in both tests were equivalent.

Conclusion: Sonography performed significantly better than CT in depicting cervical metastatic nodes. Sonography could be a useful adjunct to CT in surveying cervical metastatic nodes.