Ultrasound diagnostics in the detection of pathologies of the thyroid gland

Pathology of the thyroid gland occurs in 20% of the adult population of the globe, in certain areas this indicator exceeds 50%. At this time, there is a significant increase in thyroid diseases both among the adult population and among children and adolescents.

Bad ecology, hereditary factors, nutritional deficiency of iodine, stress, intoxication, injuries, frequent infections, concomitant diseases contribute to the development of pathological changes in the tissue of the thyroid gland. The damage caused by thyroid pathology to society is enormous.

How to recognize the disease before it strikes?

Early diagnosis and prevention is the answer to this question. For a long time, the diagnosis of thyroid gland diseases was based on the data of palpation, visual examination and history. In some cases, these methods do not provide sufficient information about the already existing pathology, which requires urgent treatment. The appearance of new ultrasound devices using linear multifrequency sensors opened a new era in the diagnosis of diseases of this organ.

Ultrasound examination (ultrasound) with the complex application of the latest methods and technologies provides complete information about the state of the thyroid gland, surrounding tissues and lymph nodes of the neck. Ultrasound of the thyroid gland is used as a screening test, which allows to detect primary pathology in patients, which they do not even suspect, because often the disease is asymptomatic. It is also possible to carry out dynamic ultrasound monitoring of thyroid pathology against the background of treatment, postoperative changes, detection of recurrence of diseases, such as nodular goiter, thyroid cancer.

Ultrasound makes it possible to fully judge the location of the thyroid gland, characterize its shape, size, volume, borders, contours, internal structure, detect focal pathology, anatomical features of its structure and location, evaluate the blood supply of both the entire gland and its individual areas.

The use of dopplerographic methods (which assess the nature of blood flow), three-dimensional image reconstruction significantly increases diagnostic information, allows differential diagnosis of various pathological changes in the thyroid gland. Ultrasound of the thyroid gland does not require special training, is not related to ionizing radiation, and is completely safe for the patient. The tactics of further examination and treatment depend on the ultrasound results.

The structure of the thyroid gland

Normally, the thyroid gland is located in the middle-lower part of the front surface of the neck (from the thyroid cartilage to the supraclavicular region). The iron has right, left lobes and an isthmus. As a rule, one of the particles is slightly larger than the other, more often the right. The thyroid gland is a parenchymal organ consisting of follicles (small bubbles that produce colloid). Normally, the volume of the thyroid gland in women is -4.55-19.32 cm3, in men -7.7-22.6. cm 3. The thyroid gland produces thyroid hormones - thyroxine and triiodothyronine, which participate in all metabolic processes in the body.

What diseases of the thyroid gland can be detected by ultrasound?

Anomalies of thyroid gland development. As a rule, these are congenital anomalies caused by a violation of embryogenesis (migration to its typical place). Agnosia - absence of a gland. Hemignesia - the absence of one of the lobes. Hypoplasia - small size of the gland. Clinical manifestations of these abnormalities are often hypothyroidism (decreased function). Other anomalies include additional lobes, ectopy (location of the thyroid gland in an atypical place, for example, under the tongue, behind the sternum).

Non-neoplastic diseases of the thyroid gland or diffuse lesions. Such diseases include diffuse hyperplasia of the gland (increase in size), diffuse changes in the gland without an increase in size. These conditions are often caused by iodine deficiency, hormonal disruption, insufficient utilization of iodine against the background of medication.

Diffuse lesions also include subacute thyroiditis, chronic autoimmune thyroiditis, nodular form of hyperthyroidism accompanied by thyroid hyperfunction, hypothyroidism (reduced thyroid function).

When detecting this pathology with the help of ultrasound in the gray scale, it is impossible to overestimate the high diagnostic informativeness of the Doppler method (color Doppler mapping and pulsed wave Doppler) of the vessels of the thyroid gland.

With the help of this method, the number of parenchymal vessels in the structure of the tissue (cartogram), the density of color signals is estimated, the speed parameters of the blood flow are studied, and indices are calculated that allow determining the nature of the blood flow in the tissue.

A function such as energy mapping (EC) allows blood flow to be determined even in the smallest vessels with very low blood flow velocities.

According to the data of this study, it is possible to assume the nature of the changes occurring in the structure of the thyroid gland, which helps the clinician to determine the tactics of examination and treatment. Likewise, the dynamic implementation of these methods against the background of treatment allows us to assess how effective the therapy used is.

The third group is focal lesions of the thyroid gland. These include benign lesions - nodular, multinodular goiter, cysts, follicular and non-follicular adenomas. And a particularly dangerous group of diseases, which are asymptomatic for a long time, but deal a terrible blow to the body, is thyroid cancer.

It has now been established that thyroid cancer occurs in every fifth patient with solid thyroid nodules. Despite the fact that thyroid cancer is treated very successfully, in 95% of cases, its detection in the early stages frees patients from a lot of problems, significant financial costs, and loss of time for numerous visits to doctors.

Early detection of this disease allows organ-sparing surgery to be performed in a number of cases, and severe treatment of metastatic lesions of other organs can be avoided. It is important to detect changes in the early stages, when there is no invasion (germination of the capsule of the cancer node).

For the third group of diseases, it is necessary to apply the entire range of ultrasound research methods. This study is in the usual gray scale, which allows you to evaluate the size of the node, the clarity of its contours, the nature of the structure, the relationship with the capsule of the gland and the surrounding tissues, and conduct dynamic monitoring of the detected changes. Unclearness, uneven contours of the node, deformation of the gland capsule, the presence of calcifications in the structure of the node are warning signs of cancer. Also, the use of color dopplerography makes it possible to assess the nature of the blood supply to the nodes.

There are 4 types of vascular patterns of the thyroid gland in ultrasound Doppler:

Absence or weak expression of signals,

Blood flow on the periphery of education,

Mixed blood flow - on the periphery and in the center of the node,

Only in the center of the node.

The presence of mixed, active blood flow in the node is also a warning sign of cancer.

In patients of the first and second groups, it is necessary to conduct an ultrasound of the lymph nodes of the neck, which are the first to respond to pathological changes occurring in the thyroid gland. Identified structural changes in lymph nodes help judge the nature of pathological changes in the thyroid gland.

For many years, the search for signs that allow differential diagnosis between benign and malignant lesions of the thyroid gland has been conducted. Still, the gold standard for the diagnosis of focal pathology is a fine-needle aspiration biopsy of the thyroid gland under ultrasound control (TAB). With the help of this method, early detection of thyroid cancer is possible. Under ultrasound guidance, it is possible to select the exact area of the thyroid gland where structural changes are most pronounced.

Non-palpable nodes detected by ultrasound should also be punctuated using ultrasound guidance. Ultrasound guidance during fine-needle aspiration biopsy of nodes located close to the trachea, esophagus, and main vessels allows to avoid their injury. The method is highly informative, effective, non-traumatic for the gland, since the material is taken with a thin needle, without tearing out pieces of tissue.

Disposable needles are used for thyroid biopsy, which protects the patient from infection with severe viral infections. Biopsy is performed on an outpatient basis.

Currently, there is a growing trend in the world towards organ-preserving tactics in the management of patients with benign thyroid nodules. But for this, it is necessary to know the nature of changes in nodular formations, which is possible with the help of a biopsy.

The doctor-endocrinologist compares the results of ultrasound of the thyroid gland, clinical and laboratory data, and also determines the tactics of examination and treatment. Moreover, it should be taken into account that a combination of several pathological processes in the thyroid gland is possible, for example nodular goiter and chronic thyroiditis, nodular goiter and cancer, adenoma and nodular goiter, and only an experienced endocrinologist can make a competent diagnosis, prescribe the correct treatment and examination, thereby significantly improve the patient's quality of life.