X-ray diagnosis of salivary gland diseases

The large salivary glands (parotid, submandibular, sublingual) have a complex tubular-alveolar structure: they consist of parenchyma and ducts of the fourth order (respectively interlobar, interlobular, intralobular, intercalated, striated).

Parotid gland. Its growth and formation occur up to 2 years. The size of the gland in an adult: vertical 4-6 cm, sagittal 3-5 cm, transverse 2-3.8 cm. The length of the parotid (Stenon's) duct is 40-70 mm, diameter 3-5 mm. In most cases, the duct has an ascending direction (obliquely from back to front and up), sometimes - descending, less often its shape is straight, geniculate, arcuate or bifurcated. The shape of the gland is irregularly pyramidal, trapezoidal, sometimes crescent-shaped, triangular or oval.

To examine the parotid gland, radiographs are taken in the frontal-nasal and lateral projections. In the frontal-nasal projection, the branches of the gland are projected outward from the lower jaw, and in the lateral projection, they are superimposed on the branch of the lower jaw and the retromandibular fossa. Leaving the gland at the level of the anterior edge of the branch, the duct opens into the vestibule of the oral cavity corresponding to the crown of the second upper molar. On frontal-nasal radiographs, there is a projection shortening of the duct. The most optimal conditions for studying the duct are created on orthopantomograms.

The submandibular salivary gland has a flattened-round, ovoid or elliptical shape, its length is 3-4.5 cm, width 1.5-2.5 cm, thickness 1.2-2 cm. The main submandibular (Wharton) excretory duct has a length of 40-60 mm, a width of 2-3 mm, at the mouth up to 1 mm; as a rule, it is straight, less often arcuate, opens on both sides of the frenulum of the tongue.

The dimensions of the sublingual salivary gland are 3.5 x 1.5 cm. The sublingual (Bartholin's) excretory duct is 20 mm long, 3-4 mm wide, and opens on both sides of the frenulum of the tongue.

Due to anatomical features (the narrow duct opens in several places in the sublingual fold or into the submandibular duct), it is not possible to perform sialography of the sublingual gland.

Involutional changes in the large salivary glands are manifested by a decrease in the size of the glands, lengthening and narrowing of the lumen of the ducts occurs, they acquire a segmental, bead-like appearance

Depending on the etiology and pathogenesis, the following diseases of the salivary glands are distinguished:

1. inflammatory;
2. reactive-dystrophic sialosis;
3. traumatic;
4. tumor and tumor-like.

Inflammation of the salivary gland symptoms manifest themselves in the form of inflammatory diseases of the salivary gland duct, and is called "sialodochit", parenchyma of the gland - "sialadenitis". Infection of the parenchyma of the salivary glands occurs through the ducts from the oral cavity or hematogenously.

Acute inflammation of the salivary gland is a relative contraindication to sialography, as retrograde infection is possible when a contrast agent is administered. The diagnosis is established based on the clinical picture of the results of serological and cytological studies of saliva.

Chronic nonspecific symptoms of inflammation of the salivary glands are divided into interstitial and parenchymatous.

Depending on the severity of changes in the gland, three stages of the process are distinguished on sialograms: initial, clinically expressed and late.

Radiological examination methods include non-contrast radiography in various projections, sialography, pneumosubmandibulography, computed tomography and their combinations.

Chronic parenchymatous sialadenitis affects mainly the parotid glands. In these cases, lymphohistiocytic infiltration of the stroma is observed, and in places, duct desolation is noted in combination with their cystic expansion.

At the initial stage, the sialogram reveals rounded accumulations of contrast agent with a diameter of 1-2 mm against the background of unchanged parenchyma and ducts.

In the clinically expressed stage, the ducts of the II-IV orders are sharply narrowed, their contours are smooth and clear; the gland is enlarged, the density of the parenchyma is reduced, a large number of cavities with a diameter of 2-3 mm appear.

In the late stage, abscesses and scarring occur in the parenchyma. Multiple accumulations of contrast agent of various sizes and shapes (mostly round and oval) are visible in the cavities of abscesses (their diameter is from 1 to 10 mm). The IV and V order ducts are narrowed on the sialogram and are absent in some areas. The oily contrast agent is retained in the cavities for up to 5-7 months.

Chronic interstitial sialadenitis is characterized by stromal proliferation, hyalinization with replacement and compression of the parenchyma and ducts by fibrous tissue. The parotid glands are predominantly affected, and the submandibular glands are less frequently affected.

At the initial stage of the process, narrowing of the ducts of the HI-V orders and some unevenness of the image of the parenchyma of the gland are revealed.

In the clinically expressed stage, the ducts of the II-IV orders are significantly narrowed, the density of the parenchyma is reduced, the gland is enlarged, the contours of the ducts are smooth and clear.

In the late stage, all ducts, including the main one, are narrowed, their contours are uneven, and in some areas they do not contrast.

The diagnosis of specific chronic sialadenitis (in tuberculosis, actinomycosis, syphilis) is established taking into account serological and histological studies (detection of drusen in actinomycosis, mycobacteria in tuberculosis). In patients with tuberculosis, detection of calcifications in the gland on an X-ray is of great diagnostic importance. Multiple cavities filled with a contrast agent are detected on a sialogram.

Chronic sialodochit. The parotid gland ducts are predominantly affected.

At the initial stage, the sialogram shows that the main excretory duct is unevenly dilated or unchanged, and the ducts of the I-II, sometimes II-IV orders, are dilated. The dilated sections of the ducts alternate with unchanged ones (rosary-like appearance).

In the clinically expressed stage, the lumen of the ducts is significantly dilated, their contours are uneven but clear. Areas of dilation alternate with areas of narrowing.

In the late stage, the sialogram shows alternating areas of dilation and narrowing of the ducts; sometimes the course of the ducts is interrupted.

Salivary stone disease (sialolithiasis) is a chronic inflammation of the salivary gland, in which concretions (salivary stones) form in the ducts. The submandibular gland is most often affected, less often the parotid gland and very rarely the sublingual gland. Salivary stone disease accounts for about 50% of all cases of salivary gland diseases.

One or more stones are located mainly in the places of bending of the main duct, their mass fluctuates from several fractions of a gram to several tens of grams. They are localized in the submandibular salivary gland.

The diagnosis is established after an X-ray or ultrasound examination. Stones can be located in the main excretory duct or in the ducts of the I-III orders (they are usually called "gland stones"). In most cases, the stones are calcified and are determined on the X-ray as clearly defined dense shadows of a round or irregularly oval shape. The intensity of the shadow is variable, determined by the chemical composition and size of the stones. To diagnose stones in the Wharton duct of the submandibular salivary gland, intraoral X-ray of the floor of the mouth in bite is used, and if "gland stones" are suspected, X-ray of the lower jaw in the lateral projection. When X-raying the parotid salivary gland, X-rays of the lower jaw are taken in the lateral projection and images in the frontal-nasal projection.

Sialography using water-soluble preparations is of particular importance for the purpose of detecting non-calcified (radio-negative) stones and assessing changes in the salivary gland. On sialograms, stones look like a filling defect. Sometimes they are enveloped, soaked in a contrast agent and become visible on the image.

At the initial stage, the sialogram shows the expansion of all ducts located behind the calculus (the stage of saliva retention).

In the clinically expressed stage, areas of expansion and narrowing of the ducts alternate.

In the late stage, as a result of repeated exacerbations, cicatricial changes occur, leading to the formation of filling defects. The contours of the gland ducts are uneven.

X-rays reveal stones of 2 mm or more in size; stones located in the gland are more visible.

The group of reactive-dystrophic processes includes Sjogren's disease and Mikulicz's disease.

Sjogren's disease and syndrome. The disease manifests itself as progressive atrophy of the parenchyma of the salivary glands with the development of fibrous connective tissue and lymphoid infiltration.

In the initial stage of the disease, there are no changes in the sialograms. Later, extravasates appear due to increased permeability of the duct walls. In the late stages, round and oval cavities with a diameter of up to 1 mm appear, the ducts of the III-V orders are unfilled. As the disease progresses, the cavities increase, their contours become unclear, the ducts are not filled, the main duct is dilated. In general, the sialographic picture is the same as in chronic parenchymatous sialadenitis.

Mikulicz disease. The disease is accompanied by lymphoid infiltration or development of granulation tissue against the background of a chronic inflammatory process.

On the sialogram, the main duct of the salivary gland is narrowed. Lymphoid tissue, squeezing the ducts at the gates of the lobules, makes it impossible to fill the smallest ducts with contrast agent.

Benign and malignant formations of the salivary glands. On sialograms of malignant tumors, due to their infiltrative growth, the boundary between normal tissue and the tumor is unclear, and a filling defect is visible in the tumor. In benign tumors, a filling defect with clear contours is determined. Filling of the ducts in the peripheral parts of the tumor allows us to assume the benign nature of the process. Diagnostic capabilities are expanded by combining sialography with computed tomography.

If a malignant tumor is suspected, sialography is preferably performed using water-soluble contrast agents, which are released and absorbed faster than oil-based ones. This is important, since some patients are planned to undergo radiation therapy in the future.

Ultrasound diagnostics of salivary gland diseases. The method allows diagnosing sialadenitis at different stages of its development, differentiating it from lymphadenitis of intraglandular lymph nodes.

Stones are clearly visible on echograms, regardless of their degree of mineralization.

In case of neoplasms of the salivary glands, it becomes possible to clarify their localization and prevalence.