ABSTRACT
Computed tomography (CT) or magnetic resonance imaging (MRI) of the head and neck is frequently performed to evaluate tumors. Most primary head and neck cancers are mucosal lesions, and their mucosal extent can far better be evaluated by the clinician than with even sophisticated imaging methods such as CT or MRI. Indeed, imaging plays little role in the initial detection and characterization of head and neck malignancies. However, these tumors do have a tendency to spread submucosally. This extension into the deeply lying tissue planes is not always easy, and sometimes impossible, to detect by clinical examination. Some regions, such as the base of the skull, pterygopalatine and infratemporal fossa, orbits, and brain are beyond clinical evaluation, but critical management decisions have to be made based on involvement of these structures; imaging findings are of the utmost importance in such cases. Perineural and/or perivascular spread, eventually leading to tumor progression or recurrences at a distance from the primary tumor, can be detected by imaging. Bone involvement, or cartilage invasion or destruction can be visualized using CT or MRI. Metastatic adenopathies can be identified, sometimes still in a subclinical stage or at places not accessible to clinical examination, such as in the retropharyngeal or paratracheal lymph nodes. All these findings can profoundly influence the staging and management of the patient with head and neck cancer. Finally, imaging may be used to monitor tumor response and to try to detect recurrent or persistent disease before it becomes clinically evident, possibly with a better chance for successful salvage.
