Utility of computed tomography findings as a predictor of carotid artery invasion by metastatic lymph nodes in head and neck squamous cell carcinoma

Purpose: Carotid artery invasion by metastatic lymph nodes in head and neck squamous cell carcinoma (HNSCC) is one of the diagnostic criteria for unresectable tumors. However, to date, the diagnostic criteria for carotid artery invasion have not been well documented. This study investigated the utility of computed tomography (CT) findings as a predictor of carotid artery invasion by metastatic lymph nodes in HNSCC. Methods: Twenty-eight patients who had metastatic lymph nodes of HNSCC attached to the carotid artery as seen on CT images before neck dissection from January 2011 to November 2017 were included. Five imaging parameters (angle of contact [AC], length of contact [LC], haziness of the carotid artery wall [HW], size of the lymph node, and involvement of the bifurcation of the carotid artery [IB]) were assessed using CT to predict carotid artery invasion. Furthermore, the utility of the combination of these five parameters was evaluated. Results: There were significant differences in AC, LC, and IB between patients with and without carotid artery invasion. There were significant differences in all combinations of the two image findings between patients with and without carotid artery invasion. In particular, the combinations of LC and HW, and LC and IB could clearly predict carotid artery invasion. Conclusion: AC, LC, and IB were useful predictors of carotid artery invasion of metastatic lymph nodes in HNSCC. This study is the first to report that IB is a useful predictor of carotid artery invasion in HNSCC.