Sialography

Sialography (also termed radiosialography) is the radiographic examination of the salivary glands. It usually involves the injection of a small amount of contrast medium into the salivary duct of a single gland, followed by routine X-ray projections. The resulting image is called a sialogram. Sialography has largely been replaced by sialoendoscopy and cross-sectional imaging, such as CT, MRI and ultrasonography. This procedure is indicated when there is recurrent swelling and pain on the face but ultrasound has not revealed any problems. If Sjögren syndrome (also known as Sicca syndrome, an autoimmune disease that affects the lacrimal and salivary glands, causing reduced tears and saliva production) is suspected, this procedure is useful. Besides, when interventional proecudre is planned such as stone removal from salivary ducts or dilatation of the strictures in the salivary gland, this procedure is also indicated. However, for those who are pregnant, with allergy to iodinated contrast, and ongoing infection or inflammation of the face, the procedure is contraindicated. Contrast agents are classified into two groups: fat-soluble contrast agents and water-soluble contrast agents. Water-soluble contrast agents can fill the finer elements of the ductal system. Fat-soluble contrast agents are viscous and can cause allergic reactions. These can also cause discomfort to the patients. Fat-soluble contrast agents do not fill finer elements of the duct. A baseline radiograph (scout film) of the required salivary gland would be taken, the duct is dilated using graded lacrimal probes, a cannula then is inserted in this salivary gland duct's opening in the mouth, then a radio-opaque fluid (contrast medium) is injected in the duct through a small tube. A series of radiographs would then be taken to determine the flow of the fluid, identify any obstructions and its location, the rate of fluid excretion from the gland.