Computed tomography in the diagnosis of parotid gland tumours.

Twenty patients with swelling of the parotid region have been examined by computed tomography (CT). CT correctly demonstrated a mass in eleven patients and correctly excluded a mass in nine patients. Five patients had primary parotid neoplasms, all of which showed higher attenuation values than normal salivary tissue. The other masses included cystic hygroma, branchial cyst, carotid sheath hamartoma and metastases in the region of the gland. Neither intravenous nor intraglandular contrast medium was necessary for diagnosis. CT is superior to sialography in demonstrating the total extent of a mass, particularly when there is involvement of the deep lobe of the gland or the parapharyngeal space. The appearance at CT following sialography with oily contrast media suggest that oil persists in the gland despite apparent complete clearing at sialography. CT should be regarded as the investigation of choice in patients with clinical features suggesting a mass in the region of the parotid.