X-ray diagnosis of salivary gland diseases

Large salivary glands (parotid, submandibular, sublingual) have a complex tubular-alveolar structure: they consist of parenchyma and IV-order ducts (respectively, interlobar, interlobular, intralobular, intercalary, striated).

Parotid gland. Its growth and formation take place 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 (stenoval) duct 40-70 mm, diameter 3-5 mm. In most cases, the duct has an ascending direction (obliquely posteriorly anteriorly and upward), sometimes descending, less often its shape is straight geniculate, arched or bifurcated. The form of the gland is incorrectly pyramidal, trapezoid, sometimes semilunar, triangular or oval.

For the purpose of examining the parotid gland, radiographs are performed in the frontal-nasal and lateral projections. In the fronto-nasal projection, the gland branches project outside of the lower jaw, and in the lateral they overlap the branch of the lower jaw and the submandibular fossa. Exiting the gland at the level of the anterior edge of the branch, the duct opens on the threshold of the oral cavity in accordance with the crown of the second upper molar. On the fronto-nasal radiographs, the projection shortens the duct. The optimal conditions for studying the duct are created on orthopantomograms.

The submandibular salivary gland has a flattened-rounded, ovate or ellipsoidal shape, its length is 3-4.5 cm, width 1.5-2.5 cm, thickness 1.2-2 cm. The main submandibular (varton) excretory duct has a length of 40 -60 mm, width 2-3 mm, in the mouth up to 1 mm; as a rule, it is straight, more rarely arched, opens on either side of the frenum of the tongue.

The dimensions of the sublingual salivary gland 3.5x1.5 cm. The sublingual (Bartholin) excretory duct has a length of 20 mm, a width of 3-4 mm, opens on both sides of the frenum of the tongue.

In connection with anatomical features (a narrow duct opens in several places of the hyoid fold or in the submandibular duct), it is not possible to produce a sublingual gland sialogram.

Involutional changes in large salivary glands are manifested by a decrease in the size of the glands, lengthening and narrowing of the lumen of the ducts take place, they acquire a segmental,

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 are manifested in the form of inflammatory diseases of the duct of the salivary gland, and was called "sialodohitis", the parenchyma of the gland is "sialadenite." 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 carrying out the sialogram, since it is possible to retrograde infection with the administration of a contrast agent. The diagnosis is established on the basis of a 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 parenchymal.

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

X-ray methods include non-contrast radiography in various projections, sialogram, pneumosubmandibulography, computed tomography and combinations thereof.

Chronic parenchymal sialadenitis affects primarily the parotid gland. In these cases, lymphohistiocytic infiltration of the stroma is observed, in places there is a desolation of the ducts in combination with their cystic enlargement.

In the initial stage, on the sialogram, rounded clusters of contrast medium 1-2 mm in diameter are detected against the background of unchanged parenchyma and ducts.

In the clinically pronounced stage, the channels of II-IV orders are sharply narrowed, their contours are even and clear; the gland is enlarged, the parenchyma density 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. Numerous different sizes and shapes (mostly rounded and oval) are seen in the cavities of abscesses (diameter from 1 to 10 mm). Protocols IV and V orders on the sialogram are narrowed, in some areas there are none. Oil contrast medium is retained in cavities up to 5-7 months.

In chronic interstitial sialadenitis, stroma proliferation, hyalinization with substitution and compression of the parenchyma and ducts with fibrous tissue are noted. Primarily affected parotid glands, less often - submandibular.

At the initial stage of the process, the narrowing of the HI-V channels is revealed and some unevenness in the image of the parenchyma of the gland.

In the clinically pronounced stage, the ducts of II-IV orders are considerably narrowed, the density of the parenchyma is reduced, the gland is enlarged, the contours of the ducts are even, clear.

In the late stage, all ducts, including the main one, are narrowed, their outlines are uneven, in some areas they are not contrasted.

Diagnosis of specific chronic sialadenitis (for tuberculosis, actinomycosis, syphilis) is established taking into account serological and histological studies (detection of drusen with actinomycosis, mycobacteria in tuberculosis). In patients with tuberculosis, the detection on the roentgenogram of calcifications in the gland has an important diagnostic value. The sialogram shows multiple cavities filled with contrast medium.

Chronic sialodohitis. Primarily parietal gland ducts are affected.

In the initial stage on the sialogram the main excretory duct is unevenly expanded or unchanged, the ducts I-II, sometimes II-IV orders, are widened. The extended sections of the ducts alternate with the unaltered (view of the rosaries).

In the clinically pronounced stage, the lumen of the ducts is significantly expanded, their outlines are uneven, but clear. The expansion sites alternate with the sites of constriction.

In the late stage on the sialogram, the areas of expansion and narrowing of the ducts alternate; sometimes the course of the ducts is interrupted.

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

One or several stones are located mainly in the areas of the main duct bending, their mass varies from several grams to several tens of grams. They are localized in the submandibular salivary gland.

Diagnosis is established after X-ray or ultrasound. Stones can be located in the main excretory duct or in ducts of I-III orders (they are commonly called "gland stones"). The stones are calcified in most cases and are determined on the roentgenogram in the form of clearly defined dense shadows of round or irregularly oval shape. The intensity of the shadow is variable, determined by the chemical composition and magnitude of the stones. To diagnose the stones of the varton duct of the submandibular salivary gland, intraoral roentgenography of the oral cavity of the oral cavity is used, and if there is a suspicion of "gland stones", the mandibular x-ray in the lateral projection. Radiographs of the parotid salivary gland produce an x-ray of the mandible in the lateral projection and pictures in the frontal-nasal projection .

In order to identify unimagined (X-ray negative) stones and assess the changes in the salivary gland, sialography with the use of water-soluble drugs is of particular importance. On sialograms stones have the appearance of a filling defect. Sometimes they are enveloped, impregnated with contrast material and become visible in the picture.

In the initial stage, the expansion of all ducts located behind the calculus (salivary retention stage) is determined on the sialogram.

In the clinically pronounced stage, the 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 detect stones 2 mm or more in size, the stones located in the gland are better seen.

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

Disease and Sjogren's syndrome. The disease manifests itself by the 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 on the sialogram. In the future, extravasates appear due to increased permeability of the duct walls. In later stages, cavities of round and oval form with a diameter of up to 1 mm, and III-V orders appear unfilled. As the disease progresses, the cavities increase, their contours become indistinct, the ducts are not filled, the main duct is enlarged. In general, the sialogram picture is the same as in chronic parenchymal sialadenitis.

Disease of Mikulich. The disease is accompanied by lymphoid infiltration or the development of granulation tissue on the background of a chronic inflammatory process.

On the sialogram the main duct of the salivary gland is narrowed. Lymphoid tissue, squeezing the ducts in the lobes of the lobes, makes it impossible to fill the smallest channels with contrast material.

Benign in malignant formation of the salivary glands. On sialograms in malignant tumors due to their infiltrative growth, the border between normal tissue and tumor is fuzzy, respectively, the tumor shows a filling defect. In benign tumors, a filling defect with clear contours is determined. Filling the ducts in the peripheral parts of the tumor suggests a benign character of the process. Diagnostic possibilities are extended by combining sialography with computed tomography.

If a malignant tumor is suspected, it is preferable to perform the sialogram using water-soluble contrast agents, which are secreted and dissolve faster than the oil ones. This is important, as in some patients radiation therapy is planned in the future.

Ultrasonic diagnosis of salivary gland diseases. The method allows to diagnose sialadenitis in different stages of their development, to differentiate them from lymphadenitis of the intra-lymph nodes.

Echograms are well visualized stones regardless of the degree of their mineralization.

With neoplasm of salivary glands it becomes possible to clarify their localization and prevalence.