Non-neoplastic process after neck dissection demonstrated on enhanced CT in patients with head and neck cancer

Head and neck radiologists should be familiar with typical post-therapeutic changes on enhanced CT after neck dissection because CT is widely used for the follow-up study in order to detect recurrent tumours at an early stage. The purpose of this study was to reveal post-therapeutic anatomical alterations and non-neoplastic processes demonstrated on enhanced CT.

Radical neck dissections were performed in 39 necks and modified radical neck dissections were performed in 8 necks. Post-operative radiotherapy was performed on 21 patients. Follow-up CT, studies were made within a period of 24 months.

On enhanced CT, the densities of soft tissues replacing the resected structures were homogeneous in 44 necks and showed no contrast enhancement in 39 necks. During the 24 months after treatment, most of the soft tissues did not increase in size and the attenuation of the soft tissue remained unchanged. In 44 of 47 necks, lymphoedema (LE) was observed around the carotid artery at an early stage, and it converged into the space between internal carotid artery and external carotid artery gradually. In patients without post-operative radiotherapy, LE was observed around the carotid artery in 17 of 23 necks at 3 months after neck dissection and disappeared rapidly thereafter. In patients with post-operative radiotherapy, LE increased until 3 months after radiotherapy and decreased slowly thereafter.

This is the first report of enhanced CT evaluation of LE around the carotid artery after neck dissection probably exacerbated by irradiation. Clinicians should be aware of LE around the carotid artery in patients with post-operative radiotherapy because of the possible risk of neck cellulitis at least 1 year after treatment.