With the use of high-frequency sound waves, the ultrasound machine can examine the structure of the major salivary glands including the parotid glands (located over the angle of the jaw) and the submandibular glands (located under the mid-portion of the jaw bone on each side). This is the same type of ultrasound machine that is used to visualize the fetus in a pregnant woman. A smooth probe covered with a gel is placed over the glands and pictures are taken by the ultrasonographer. As many as one-half to two-thirds of patients with Sjögren’s syndrome have characteristic changes in the structural features of their glands (resulting from inflammation) that are detected by ultrasonography and help secure the diagnosis. These structural changes also correlate with disease severity and can provide useful information about the expected course of the disease. On occasion, patients with enlargement or an isolated growth of their glands will require a biopsy. This can be done with a special needle, using ultrasound to guide its placement in the gland.