This study aimed to determine the diagnostic value of preoperative computed tomography (CT) and magnetic resonance imaging (MRI) in predicting the respectability. Fourteen patients with neck metastasis with clinical suspicion of carotid artery invasion from head and neck cancer were evaluated. Neck dissection was performed in all 14 patients. In 4 patients, the lymph node metastases could be dissected radically from the wall of the carotid artery (dissection group). In 10 patients, the carotid artery was invaded and resected (resection group). Eleven patients out of these patients underwent further evaluation with preoperative MRI. Both preoperative MRI and histopathological examination after surgery were obtained for 7 cases out of 10 patients with resection of the carotid artery.
Patients in the resection group had tumors more than 180° around the carotid artery in enhanced CT scans. All patients with attachments of more than 270° to the carotid artery required resection of the carotid artery. In MRI, we focused attention on the signal intensity around the carotid artery on T2-weighted images. In the resection group, all patients had some obscure part of the low signal intensity band around the carotid artery. We considered that a carotid artery was possibly involved when any part of this low signal band around the carotid artery was obscure and broken. Our study of histopathological findings of the carotid artery compared with MRI results revealed that the degrees of microscopic invasion into the outer layer of the carotid artery corresponded with those of the obscure part of the low signal band around the carotid artery.