Ultrasound examination (ultrasound) of the adrenal glands

The human endocrine system is a complex structure of organs involved in the implementation of many processes in the human body. The adrenal glands are one of the components of this structure. This paired organ is a gland located on the upper surface of the kidneys. Their main function in the human body is the production of sex hormones, mineralcorticoids and glucocorticoids.

Like other human organs, the adrenal glands are in no way immune from diseases, from the appearance of tumors or pathologies of the structure. The result of destructive processes in the adrenal glands is a violation of the hormonal background and hormonal imbalance, which can cause a variety of consequences – from hair loss to infertility. Therefore, diagnostic methods for examining the adrenal glands are an objective necessity in the world of medicine. These include ultrasound examination of the adrenal glands.

Ultrasound of the adrenal glands: the essence of the method, for which it is prescribed

Ultrasound is one of the methods of non-invasive diagnostics of the state of internal tissues and organs in the human body. The existence of ultrasound research became possible due to the discovery of the piezoelectric effect. Ultrasonic waves, the use of which underlies the technique of ultrasound, acting on single crystals of quartz or barium titanate, cause their deformation, and opposite electric charges appear on the surface of the crystals. In this case, when an alternating electric charge is applied to the crystals, ultrasonic waves are emitted. It turns out that the same piezoelectric element can both produce and receive ultrasonic waves. In ultrasound machines, this element is a sensor, or an acoustic transducer.

As for the ultrasonic waves themselves, they have a certain frequency, oscillation period, and length. For ultrasound of the adrenal glands, the frequency of ultrasound waves of 2,5-3,5 MHz is usually sufficient. These characteristics are also important in the ultrasound examination technique, as they determine the resolution of the acoustic transducer.

The most important property of ultrasonic waves is the degree of their absorption by media of different densities. This property of matter is called the level of acoustic resistance, and, in addition to the density of matter, it is also determined by the speed of wave propagation.

Based on which part of the ultrasonic wave beam is absorbed and which is reflected, the ultrasound machine recreates a picture on the monitor showing as lighter and brighter areas those places where the difference in acoustic impedance between different tissues is more important.

Pathological changes in the size or location of the adrenal glands, cysts and tumors, the consequences of inflammatory processes, hemorrhages, trauma to organs require mandatory medical intervention and therapeutic therapy.

Today, ultrasound examination of the adrenal glands is one of the recommended methods for diagnosing the condition of these organs. It is prescribed to check the suspicion of the presence of pathologies of any nature, to establish an initial diagnosis, to monitor the effectiveness of the treatment taken, as well as for preventive purposes. Less commonly, the method is used to identify the grounds for the appointment of an operation – in such cases, doctors usually prescribe computed or magnetic resonance imaging.

The structure and features of the functioning of the adrenal glands in the human body

Anatomically, the adrenal glands are located in close proximity to the upper pole of the kidneys. The organs are paired, but not symmetrical: the right gland has the shape of a triangle, and the left one is oblong, and, as it were, lies along the surface of the kidney, encircling it with a crescent. The right adrenal gland is narrower and higher than the left. It is directly adjacent to the inferior vena cava, and, except for a small part of the anterior surface, is not covered by the peritoneum. Only the lower region of the anterior plane of the organ is in contact with the liver, leaving a slight impression on it in this place. The left adrenal gland is located in the region of the upper pole of the left kidney, closer to its medial surface. In front, in its upper section, the left adrenal gland is covered with peritoneum. The left adrenal gland is adjacent to the cardia of the stomach, and is located next to the spleen and pancreas.

The structure of the adrenal glands is represented by the anterior and posterior surfaces, as well as the concave renal surface – the part that lies on the kidneys. The anterior and posterior planes have furrows. One or more grooves are visible on the anterior surface of the adrenal glands. The deepest groove is the so-called “gate” (hilus), through which the adrenal vein exits. The lymphatic vessels of the adrenal glands are also located in the gate area, and the adrenal arteries can supply blood to the organ from the anterior and posterior surfaces.

The size of the organs is quite small, and does not change significantly during a person’s life. The size and weight of the adrenal glands are individual. Their weight in a person at different ages can range from 6 to 20 grams. The length of the right adrenal gland in an adult varies from 1 to 2 centimeters, while the width should not exceed 1,5 cm, and the height – 1-2 cm. The width of the left adrenal gland is from 0,9 to 1,7 cm, length and height ranging from 1,4 to 2,6 cm.

The structure of the organs is:

• fibrous capsule;
• cortex;
• brain matter.

The fibrous capsule is a thin layer of fibrous tissue with the presence of muscle fibers. Processes extend into the thickness of the gland from the outer shell.

The cortex is thicker than the medulla, and is colored yellowish-brown, formed by glandular and connective tissue. It is responsible for the production of corticosteroids – steroid hormones with glucocorticoid or mineralocorticoid activity.

The structure of the adrenal cortex is represented by:

• glomerular zone under the capsule of the adrenal gland;
• beam zone;
• reticular zone surrounding the medulla.

Mineralocorticoids are produced in the zona glomeruli. These include aldosterone. Due to the production of this hormone, calcium ions are secreted into the urine, as well as sodium ions are reabsorbed into the circulatory system in the kidneys.

Glucocorticoids, including cortisol, are produced in the zona fasciculata. With its participation, almost all metabolic processes in the body occur, and the work of the cardiovascular system, kidneys, and the functioning of the nervous system are also regulated.

The reticular zone of the adrenal glands produces sex hormones, including dehydroepiandrosterone and androgens.

They affect the development of secondary sexual characteristics, protein synthesis and the ability of muscles to contract.

The medulla makes up about 10% of the total mass of the adrenal gland. It is located under a thick layer of cortical substance, inside the organ. Its cells produce adrenaline and norepinephrine. These hormones increase blood pressure and activate the work of the heart muscle, and also affect the metabolic processes.

Indications for ultrasound of the adrenal glands

The reasons for the appointment of an ultrasound examination of these organs may be certain symptoms and situations with which the patient is at the doctor:

• • discoloration of the skin (usually darkening);
  • chronic fatigue, weakness, fatigue;
  • sudden weight gain for no apparent reason;
  • increased blood pressure of unknown etiology;
  • the appearance of stretch marks on the skin;
  • severe muscle weakness;
  • injuries of the abdominal cavity and kidneys;
  • in men – a violation of potency;
  • in women – increased body hair growth, infertility, menstrual irregularities;

problems with puberty in adolescents.

Such symptoms may indicate the presence of hormonal disorders, including due to improper production of adrenal hormones.

In some cases, an ultrasound is prescribed to confirm the diagnosis if the doctor suspects the patient has:

• adrenal tumors and cysts;
• enlargement of the adrenal glands, their displacement;
• mechanical injury to the kidneys and adrenal glands, hematomas;
• inflammatory processes.

Contraindications: in what cases the procedure is not performed

Given the complete safety and painlessness of an ultrasound examination, it has no absolute contraindications. However, when prescribing the diagnosis of adrenal pathology by this method, the doctor takes into account some factors:

• the presence of pregnancy in women;
• skin lesions and diseases;
• wounds and damage to the integrity of the skin;
• a large amount of excess weight in the subject.

Ultrasound examination of the adrenal glands for a woman during pregnancy is recommended only as prescribed by a specialist and after consulting a gynecologist.

During pregnancy, the need of the female body for the hormones of the adrenal cortex increases. Significant mobilization of protective and adaptive mechanisms also requires the process of childbirth, accompanied by a pronounced increase in the corticosteroid function of the adrenal glands. Therefore, periods of pregnancy and childbirth require close attention to the state of the adrenal glands. At the same time, in some cases, in the early stages of pregnancy or with increased uterine tone, any unreasonable examinations and procedures associated with exposure to the abdominal area may be undesirable.

The process of studying how ultrasound can affect the development of the child continues today, and while the attending physicians try to avoid unreasonable prescribing of ultrasound of the adrenal glands to pregnant women. Although, compared with the methods of radiography or computed tomography, ultrasound diagnostics is certainly recognized as safer.

If the patient has severe skin diseases, formations and lesions caused, for example, by fungi or other microorganisms, they can interfere with the ultrasound machine’s sensor to fully interact with the skin surface.

The situation is similar with damage to the integrity of the skin. If the patient has open wounds, they must first heal, and then an examination can be carried out.

As for overweight, fatty deposits in the subcutaneous fat of the anterior abdominal wall and lumbar region simply interfere with visualizing the image of organs on the monitor of an ultrasound machine, since it is extremely difficult for ultrasonic waves to break through them.

How to Prepare for an Adrenal Ultrasound

A feature of this diagnostic method is the presence of difficulties in visualizing the structure of organs. The degree of informativeness of the obtained image of the organs will depend on how conscientiously the patient treats compliance with the preparation requirements.

Preparation starts 2-3 days before the examination date. First of all, you need to pay attention to the diet. Of course, if the patient is obese, which, in some way, interferes with the implementation of ultrasound of the adrenal glands, it will not be possible to get rid of excess weight in such a short time. But dietary restrictions before the procedure are not aimed at this – they are observed in order to reduce the level of gas formation in the digestive tract.

Excluded from the diet:

• black bread;
• milk products;
• raw fruits and vegetables;
• fatty and fried foods;
• beans;
• carbonated and alcoholic drinks.

On the eve of the procedure, in the evening before going to bed, you should take a laxative.

As part of the preparation requirements, the attending physician may refer the patient for a consultation with an endocrinologist (for example, if the treatment is carried out by a general practitioner or oncologist), as well as for blood tests for adrenal hormones. The results of the analyzes characterize the features of the work of the glands no less informative than ultrasound, MRI and CT.

It is advisable to perform an ultrasound examination of the adrenal glands on an empty stomach, therefore, 3-5 hours before the start, you should not eat or drink.

Diagnostic technique

Ultrasound of the adrenal glands is performed transabdominally, that is, through the anterior wall of the abdominal cavity. The patient is placed on the couch in a position on the stomach or on the back. The position should be comfortable and relaxed. If necessary, the doctor will ask the subject to roll over on his side or stand up straight. The lower back and abdomen are freed from clothing.

For the procedure, a special gel is applied to the area under study. It performs two functions:

• lubricating, that is, it improves the sliding of the ultrasound machine sensor over the skin;
• conductive: the gel enhances the contact of the sensor with the skin, helps to reduce interference.

According to the research scheme, first the doctor finds the right kidney, the right lobe of the liver and the inferior vena cava with a sensor. The extreme points of these organs limit the area in which the right adrenal gland is located.

For the most informative scan of the adrenal glands, the doctor may ask you to take a deep breath and hold your breath for a while.

To examine the left adrenal gland, the patient is turned over to the right side, and the region of its location is found between the lower edge of the spleen and the upper pole of the kidney.

The technique of performing an ultrasound examination of the adrenal glands is to locate their location and scan it for pathologies. In most cases, it is pathological changes or formations that will be displayed on the monitor of the device, while healthy glands may not be visualized normally. If ultrasound diagnostics did not reveal pathological changes, this is explained by the following feature: a healthy organ is not always visualized, but it is possible to see an increase or neoplasm of the adrenal gland in almost all cases. This is due to the fact that the size of the glands is very small, and they are not always amenable to visualization by means of ultrasound.

How the results of ultrasound of the adrenal glands are deciphered

The specialist who performed the procedure, after its completion, using the data recorded in the process and the obtained ultrasound images, draws up a conclusion. To do this, he needs to decipher the results of the study, using all his skills and professional knowledge.

Thanks to the ultrasound procedure, the doctor has the opportunity to clarify the anatomical characteristics of the organs: their size and location, structure.

Determination of the location of the right adrenal gland occurs in 90% of studies, the left – in only half of the cases. The identification of the left organ is hindered by the gas bubble of the stomach, as well as the intestinal loop. Due to the lack of a good “acoustic window”, adrenal pathology is often not diagnosed precisely on the left. The echographic dimensions of normal adrenal glands are: length on the right 1.8-2.8 cm; length on the left 1.6-2.5 cm; thickness 1,1-1,6 cm

Normally, the right adrenal gland is located in the upper medial plane of the right kidney.

Its left pair is located in the zone of the left kidney and aorta.

The results of diagnostics make it possible to identify hematomas, hyperplasia, cysts, tumor formations, and foci of inflammation. In the early stages and with small sizes of pathological changes, ultrasound can be the main screening diagnostic method, however, for a more detailed picture, CT and MRI of the abdominal cavity and retroperitoneal organs are recommended.

Adrenal hematomas can be a birth injury of newborns (often develop in the perinatal period as a result of perinatal hypoxia), and in adults they can occur as a result of sepsis, anticoagulant therapy, pregnancy, and severe traumatic lesions. On ultrasound examination, adrenal hematoma is difficult to differentiate with a tumor process, inflammatory changes in the adrenal glands, adrenal necrosis that has developed as a result of thrombosis of the adrenal vein.

Hyperplasia of the adrenal gland – an increase in the size of the organ. Sometimes the proliferation of tissues of the adrenal gland causes endocrine disorders. The results of the examination only suggest the presence of hyperplasia, after which the attending physician prescribes an MRI or CT scan with contrast to clarify the diagnosis.

Adrenal cyst is a descriptive term used to refer to a true cyst, pseudocyst, or cystic mass. A true adrenal cyst is a rather rare phenomenon, it is laid during the embryonic development of the body, and for many years a person does not know about its existence due to the absence of any specific signs. It is quite difficult to identify an adrenal cyst and differentiate it from a subcapsular cyst of the kidney. An adrenal cyst is defined as a solitary unilateral round or oval mass with an anechoic structure with a hyperechoic capsule and distal echo enhancement.

Neoplasms of the adrenal glands during ultrasound can usually be visualized – if – the size reaches two or more centimeters. Neoplasms in these organs can cause significant harm to a person. If the tumor grows up to 4-5 centimeters, it begins to put pressure on neighboring organs and interfere with their work. Another danger is that some tumors can produce large portions of hormones, thereby causing a hormonal imbalance in the body. An adrenal tumor is visualized on ultrasound as a hypoechoic mass, defined on the right between the vena cava and the upper pole of the kidney (where it can easily cause vena cava compression syndrome) or on the left, between the aorta and the upper pole of the kidney.

Benign formations – aldosteroma and adenoma – can be visualized by ultrasound as homogeneous, round or oval formations up to 5-6 centimeters in size, with low echogenicity and even clear. They affect the adrenal cortex.

Hormonally active tumor of the adrenal medullary substance is pheochromocytoma or pheochromoblastoma. They can reach large sizes, and on ultrasound examination of the adrenal glands they are defined as an irregularly shaped hyperechoic area with small anechoic areas. The leading clinical symptom of this pathology is usually malignant arterial hypertension.

Such a neoplasm often develops along with thyroid cancer.

Ultrasound of the adrenal glands: advantages and disadvantages of the method

Positive feedback about this diagnostic method, both from physicians and from patients, indicates that the method is affordable and inexpensive, completely painless.

Ultrasound has a small list of relative contraindications, and is also recognized as one of the most harmless methods of non-invasive examination.

Since the procedure does not involve the use of harmful X-rays, it can be repeated many times without observing any significant intervals between sessions. The process itself takes no more than 5-7 minutes.

As for the disadvantages, almost the only, but very significant of them, is the difficulty in visualizing the adrenal glands due to the fact that they are located under a layer of skin and subcutaneous fatty tissue, under several layers of muscles, etc. intestines, fat in the root of the mesentery of the intestine, and retroperitoneal fatty tissue. When passing through all these obstacles, the power of the ultrasound wave is significantly reduced, so it is difficult to achieve a good level of visualization.

Ultrasound of the adrenal glands is rarely performed as an independent examination. Basically, it is included in the procedure for ultrasound of the kidneys and bladder, or carried out together with ultrasound of the vessels of the kidneys. This method is considered a safe, relatively informative way to determine the primary diagnosis or follow-up tactics to confirm the diagnosis. It is prescribed for adults and children, and if necessary, an ultrasound examination of the adrenal glands is allowed for newborns.