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Thyroid X-ray
Last reviewed: 05.07.2025
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Recognition of endocrine gland diseases is one of the brightest pages of radiation diagnostics. With the help of radiation methods, the doctor determines changes in the structure of the gland and focal formations in it. Moreover, he can detect and quantitatively evaluate the dysfunction of each gland and the "governing bodies" of the hormonal hierarchy - the hypothalamus and pituitary gland. However, we must not forget that the main indicator - the level of hormones in the peripheral blood - does not always and does not fully reflect the patient's condition, since it depends not only on the function of the endocrine glands, but also on other regulatory mechanisms. In this regard, when assessing the results of radiation studies, it is necessary to take into account the anamnestic data and the clinical picture of the disease.
Radiation anatomy of the thyroid gland
The thyroid gland is located in the anterior region of the neck in front of the trachea. It is horseshoe-shaped with a concavity facing backwards and consists of two unequal lobes connected by an isthmus. Sometimes there are additional thyroid glands (on the neck, in the area of the root of the tongue, in the chest cavity), which can be detected using radiological methods, especially scintigraphy.
X-ray anatomy of the thyroid gland
Radiological study of thyroid physiology
The state of iodine metabolism and thyroid function are assessed by radionuclide studies. As is known, the thyroid gland performs three main functions:
- uptake of iodides from the blood;
- synthesis of iodine-containing thyroid hormones;
- the release of these hormones into the blood.
X-ray examination of thyroid gland physiology
Clinical and radiological syndromes and diagnostic programs for thyroid diseases
In order to carry out rational treatment, it is necessary to determine the morphological changes in the thyroid gland and the level of endocrine function of all glands that regulate iodine metabolism in the body.
If it is impossible to conduct a radioimmunological analysis, and also if it is necessary to establish the state of the intrathyroid stage of iodine metabolism, thyroid radiometry is performed.
Diffuse goiter. A distinction is made between diffuse enlargement of the entire thyroid gland in the absence of individual palpable nodes and diffuse-nodular goiter when one or more nodes develop in the enlarged organ. In both forms, the function of the gland can be normal, enhanced, or weakened.
Sometimes the thyroid gland is located behind the sternum ("substernal goiter"). The shadow of such a goiter appears on radiographs and especially on tomograms. Scintigrams allow it to be distinguished from a tumor formation in the mediastinum.
Toxic nodular goiter. In case of nodular lesions of the thyroid gland, it is advisable to start the examination with sonography. Ultrasound scanning allows confirming the presence of nodes in the gland, establishing their macromorphological structure, and distinguishing them from cysts. The next stage of distinguishing nodular formations is scintigraphy. Most nodular formations, with the exception of toxic adenoma, give a defect in the accumulation of radiopharmaceuticals on the scintigram - a "cold" focus.
Benign nodular formation. Benign formations of various natures are found in the thyroid gland: cysts, adenomas, nodes in some forms of colloid goiter, areas of limited thyroiditis, cicatricial fields. All of them on scintigrams determine the area in which the radiopharmaceutical does not accumulate or accumulates very weakly, i.e. a "cold" node. Based on the results of a radionuclide study, it is difficult, and sometimes impossible, to establish its origin. In this case, clinical data, sonography and biopsy results help in diagnosis.
By the nature of the structure, benign formations are divided into solid, cystic and mixed. A solid node consists of dense tissue, a cystic node is a cavity with liquid contents, and a mixed node includes both dense tissue and cysts.
Sonograms allow to immediately identify all cystic formations. A cyst is defined as a round or oval body with smooth contours and is characterized by uniform echo-negativity. Follicular adenoma looks like a formation of a regular round shape with reduced echogenicity with some heterogeneity of structure. The outlines of the adenoma are usually smooth. Denser areas in it are determined by increased echogenicity; in such cases, a rim of reduced echogenicity around can be seen, caused by peri-nodular edema of the thyroid tissue. A "cold" lesion in limited thyroiditis produces an area of low echogenicity with unclear outlines and small additional structures inside.
A malignant space-occupying lesion. A cancerous nodule in the thyroid gland is usually solitary. On scintigrams, it usually appears as a "cold" lesion. Its ultrasound image is difficult to interpret, as it varies depending on the tumor structure. Most often, sonograms show a low-echo density nodule with fairly clear but uneven contours. However, there are tumors with increased echogenicity. The image of the nodule is non-uniform: areas of varying echogenicity stand out against its background. There is no echo-negative rim around the tumor. Instead, very small calcifications in the form of short lines or foci are often visible along the periphery of the nodule.
Hypothyroidism. There are four forms of hypothyroidism: primary, secondary, tertiary, and iodine-deficiency. In primary hypothyroidism, hormone formation in the thyroid gland itself is disrupted; in secondary hypothyroidism, the thyrotropic function of the pituitary gland is reduced. Tertiary hypothyroidism is caused by suppression of the hypothalamus. Finally, iodine-deficiency hypothyroidism develops when there is insufficient iodine in food and water.
Parathyroid adenoma
The parathyroid glands control all calcium metabolism in the body. Hyperfunction of one or both glands leads to primary hyperparathyroidism. The level of parathyroid hormone in the blood is determined by radioimmune testing. This is a very sensitive reaction, which makes it possible to establish hyperparathyroidism before changes in the bones appear on X-rays. In approximately 80% of cases, hyperparathyroidism is associated with the development of a single parathyroid adenoma. Secondary hyperparathyroidism is usually explained by hyperplasia of both glands in chronic kidney disease.