[Modern radiologic diagnosis of the nasopharynx]

Abstract

The nasopharynx is one of the most delicate areas of the head and neck for diagnosis and treatment. Biopsies can be taken easily under local anaesthesia; however, since many tumours in this particular region grow in the submucosa, biopsies taken from the superficial tissue layers might not show any signs of malignancy. Thus, diagnostic imaging has become important in evaluating the nasopharyngeal region. Until the early seventies, when computed tomography (CT) was introduced, conventional tomography was commonly used. Since the development of CT and --particularly--the "high-resolution" technique, tumour infiltration of the skull base and parapharyngeal space as well as intracranial extension can be evaluated sufficiently and the different compartments of the soft tissue can be clearly distinguished due to their varying density. Magnetic resonance imaging (MRI)--a new technique introduced a few years ago--yields a much better soft tissue contrast than CT. Contrast enhancement after application of Gd-DTPA provides further information on tumour outlines and architecture. Benign lesions can be distinguished from malignant tumours, as well as recurrent tumours from postoperative fibrosis. MRI can also show large bony defects while minor infiltrations of the skull base are detected by HR-CT. Both MRI and CT are well-established methods in diagnosing diseases of the nasopharynx and its surroundings. For evaluations of the vascular supply prior to operation digital subtraction angiography (DSA) might be necessary in some cases.