Disorders of the major salivary glands are relatively common, with a large spectrum of underlying diseases. This has led to a variety of classifications. However, the presenting symptoms and complaints allow a broad division into six main categories:
The important causes of these complaints are summarized in Table 32.1.
|Salivary gland complaint||Cause|
|Acute intermittent generalized swelling|
The most common disorder of the major salivary glands is obstruction caused either by salivary stones (calculi) or stricture of the ducts. A large proportion of salivary calculi are radiopaque (approximately 40–60% in the parotid and 80% in the submandibular glands) so patients presenting with obstructive symptoms of acute intermittent swelling require routine radiographs to determine the presence and position of the stone(s), as shown in Fig. 32.1.
Sialography can be defined as the radiographic demonstration of the major salivary glands by introducing a radiopaque contrast medium into their ductal system. It is also very effective for the diagnosis of obstruction whether caused by stones or strictures. It is widely used and is probably still the most common specialized salivary gland investigation.
The relevant duct orifice needs to be found clinically, probed and dilated, and then cannulated. This is shown in Fig. 32.2. together with a diagram of the normal anatomy of the major salivary glands and ducts. The contrast medium can then be introduced.
Three main techniques are available for introducing the contrast medium, as described later. When this is complete, the filling phase radiographs are taken, ideally at least two different views at right angles to one another.
The cannula is removed and the patient allowed to rinse out. The use of lemon juice at this stage to aid excretion of the contrast medium is often advocated but is seldom necessary. After 1 and 5 minutes, the emptying phase radiographs are taken, usually oblique laterals. These films can be used as a crude assessment of function.
Most radiology departments use aqueous solutions. Their relative advantages and disadvantages are summarized in Table 32.3.