Sialography Dx

Description: Sialography is an imaging modality used to identify salivary gland disorders and salivary duct architecture. Interest in sialography has waned with the advent of less invasive imaging modalities, including ultrasonography, scintigraphy, and MRI.

Anatomy: Parotid glands drain via the Stensen duct opposite the upper second molar. The submandibular glands drain via the Wharton duct lateral to the lingual frenulum. Sublingual glands drain via smaller ducts in to the oral cavity.

Method: A water-soluble contrast agent is instilled after cannulation of the parotid duct or submandibular ducts. Visualization of ductal architecture may be achieved with fluoroscopy or multiple view radiographs, although digital subtraction and computed tomography techniques may also be used. Secretory sialography is primarily used to assess glandular function The use of an oral sialogogue (such as citric acid) allows a subjective indication of delayed emptying from functional or obstructive causes. Interventional sialographic methods allow dilation of ductal strictures or removal of calculi.

Complications: The procedure has a very low complication rate. Allergic reactions, worsening of local inflammation, or infection has rarely been reported.

Abnormal in: Abnormal function or structure can be seen in Sjögren’s syndrome, sialectasis, sialadenitis, sarcoidosis, human immunodeficiency virus–related salivary disease, benign lymphoepithelial proliferation, trauma, or laceration. It may be helpful in distinguishing benign from malignant tumors. As many as 15% of autoimmune patients (e.g., RA, SLE, scleroderma) will have abnormal sialographic studies, even in the absence of xerostomia or secondary Sjögren’s syndrome. The results of sialography, MRI sialography, and labial biopsies often overlap. Chronic sialadenitis shows decreased secretion and increased stasis.

Indications: Sialography is used to evaluate strictures, calculi, inflammatory lesions, or trauma. It may be indicated when symptoms (xerostomia) are not otherwise explained by age, medications, or illness. It is also indicated with chronic parotitis or recurrent sialoadenitis to exclude stricture or calculus. It is not indicated for the evaluation of mass lesions, for which US and MRI are more effective tools.

Contraindication: Allergy to iodine or acute sialadenitis.

Alternatives: Although sialography, scintigraphy, and/or minor labial gland biopsy may be used in the diagnosis and assessment of Sjögren’s syndrome, this clinical and serologic diagnosis seldom requires such extensive investigation. Xerostomia may be evaluated with 99mTc-sodium pertechnetate scintigraphy. Ultrasound, using power Doppler technology, is being increasingly used to identify ductal strictures, calculi, and mass lesions. Computed tomography sialography has been replaced by MRI.

Cost: Approximately $300.

BIBLIOGRAPHY

Gritzmann N, Rettenbacher T, Hollerweger A, et al. Sonography of the salivary glands. Eur Radiol 2003;13:964–975. PMID:12695816

Kalk WW, Vissink A, Spijkervet FK, et al. Parotid sialography for diagnosing Sjogren syndrome. Oral Surg Oral Med Oral Pathol Oral RadiolEndod 2002;94:131–137. PMID:12193907