Radial Diagnostics of Endocrinology – Radionuclide Diagnosis

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  1. Principles and methods of radionuclide research. Classification of radionuclide methods. (Radial Diagnostics of Endocrinology)

Radionuclide diagnostics is diagnostics using radionuclides or chemical compounds labeled with them. Radionuclides and labeled compounds approved for clinical use are called radiopharmaceuticals (RFP). Nuclides and compounds whose behavior in the body reflects the state of its organs and functional systems are used as RP. RFP uses negligible amounts of radionuclides by weight, which are called indicator quantities and do not disrupt the normal course of physiological and biochemical processes.

The principle of radionuclide diagnostics consists in the introduction of radionuclides or radiopharmaceuticals (RFP – a chemical compound labeled with a radionuclide with known pharmacological and pharmacokinetic characteristics) into the patient’s body or into biological substances taken from him (blood, tissue pieces, secretions) with the subsequent registration of radioactive radiation.

Method of Radionuclide diagnostics (In-Vivo & in-vitro) –

There are two groups of RND methods:

  • methods of “in-vivo” diagnostics, i.e. in vivo study of the kinetics and distribution of the RFP introduced into the body), and
  • methods of “in-vitro” diagnostics, i.e. measurement of the radioactivity of biological samples outside the body, after their displacement in a test tube with RFM – radioimmunoassay (RIA)

Radionuclide scanning – a method of radionuclide research; based on a two-dimensional image of the distribution of the radiopharmaceutical in the body. In clinical practice, it is used to study the kidneys, liver, lungs, thyroid gland, pancreas, brain, skeleton, etc.

 

Classification of methods –

  1. Radiometry;
    1. Laboratory (In vivo, in vitro) – a measurement of the concentration of RFP in a particular substance by its radiation.
    2. Clinical – direct measurement of the radiation intensity over a particular area of ​​the body in statics.
  2. Gamma chronometry – time-based clinical radiometry, i.e. radiometry in dynamics. Shows not only the concentration of RFP in a particular area at different periods of time but also the degree of increase and decrease in this concentration.
  3. Gamma topography;
    1. Static z-topography – allows to get an image of an organ and examine the uniformity of filling the RFP, if there are “cold” or “hot” spots.
    2. Dynamic z-topography – a sequence of static scintigrams. The method has all the advantages of static gamma topography, plus it allows you to trace the dynamics of changes in the concentration of RP in a particular focus.
  • Emission computed tomography – obtaining a tomographic section by computer reconstruction of an image obtained by rotating a detector (gamma camera). Allocate one- and two-photon (positron) ECT.
    1. Single-photon emission computed tomography – the gamma radiation of the RFP is recorded. Registration of radiation is performed on a rotating one gamma camera. Next, digital image reconstruction is performed.
    2. Positron (two-photon) emission computed tomography – γ-radiation obtained as a result of the annihilation of a proton and an electron is recorded.

 

  1. Characteristics of radionuclide diagnostic methods in vivo. (Radial Diagnostics of Endocrinology)

Scintigraphy  – The method of visualizing an organ by the spatial distribution of the RFP in it with the subsequent registration of photons using a scintillation detector or detectors. The method makes it possible to assess the morphological and functional state of the organ. There are several types of scintigraphy.

  1. Static planar scintigraphy – its distribution in the organ is recorded by a stationary detector that captures the entire organ in the field of view. The method is used to detect tumor lesions of parenchymal organs.
  2. Whole-body scintigraphy – It is widely used in the study of the bone skeleton – osteo-scintigraphy to identify multiple lesions by the pathological process, for example, the search for metastases.
  • Dynamic scintigraphy – This allows, in addition to anatomical, to study the functional characteristics of organs, for example. the excretory function of the liver, filtration and excretory function of the kidneys, etc.
  1. Immunoscintigraphy –  fairly accurate method for diagnosing malignant neoplasms. The widespread application of the method is inhibited by a limited set of specific monoclonal antibodies.

 

RFP or radiopharmaceuticals

Application area

Brain Tc-pertechnetate,

a)      99 m Tc-TPA,

b)      99 m Tc-HMPAO,

c)       18 F-FDG

Radionuclide angiography, Perfusion SPECT – detection of heart attacks PET – glucose metabolism
Thyroid

a)      123 I-sodium iodite,

b)      99 m Tc-pertechnetate

Scintigraphy – thyrotoxicosis, goiter
Parathyroid glands

a)      201 Tl-chloride

b)      99 m Tc-MIBI

Scintigraphy – neoplasms
Salivary glands

a)      99 m Tc-pyrophosphate

b)      99 m Tc-diphosphonate

Scintigraphy – neoplasms, xerostomia
Lungs

a)      99 m Tc-DTPA

b)      99 m Tc-MMA

c)       67 Ga-citrate

Ventilation-perfusion SPECT – PE Regional perfusion – COPD, bronchiolitis, cancer
Heart

a)      201 Tl-chloride

b)      99 m Tc-MIBI

c)       18 F-FDG

Perfusion SPECT – microcirculatory disorders of the myocardium, prognosis of AMI. PET – assessment of myocardial viability
Liver and biliary tract

a)      99 m Tc-bromezide

Dynamic scintigraphy – examination of the excretory function of the liver, dyskinesia
Kidney

a)      99 m Tc-DTPA

b)      99 m Tc-MAG

Dynamic scintigraphy – examination of kidney function.
Bone skeleton

a)      99m Tc-technifor

Whole-body scintigraphy – metastases, neoplasms, osteomyelitis
Tumors of internal organs

a)      99 m Tc-MAb (monoclonal antibodies)

b)      67 Ga-citrate

c)       18 F-FDG

Immunoscintigraphy. Scintigraphy (visualization of tumors based on a “hot” focus) PET – differentiation of malignant and benign tumors, diagnosis of tumor recurrence, control of the effectiveness of chemotherapy

 

  1. Radioimmunological analysis – RIA (radio competitive microanalysis): characteristics of the method, indications, and the principle of obtaining diagnostic information. (Radial Diagnostics of Endocrinology)

Principle – RIA is based on the phenomenon of competition: the binding of antibodies to an antigen labeled with a radioactive isotope is suppressed in the presence of an unlabeled antigen.

The RIA technique is simple and includes the following main steps:

  1. A labeled antigen and a sample (containing an unknown amount of unlabeled antigen) are added to the antibody solution. The concentration of antibodies in the reaction mixture is selected so that the number of binding sites is much less than the total number of antigens. The concentration of the labeled antigen must exceed the maximum possible concentration of the antigen in the sample.
  2. The reaction mixture is incubated at a certain temperature. Labeled and unlabeled antigens competitively bind to antibodies to form immune complexes containing either labeled or unlabeled antigen. Thus, by the end of incubation, labeled and unlabeled immune complexes, as well as free labeled and unlabeled antigens, are present in the reaction mixture. The amount of labeled immune complexes is inversely proportional to the amount of unlabeled antigen in the sample.
  3. To estimate the number of labeled immune complexes, they must be separated from the free labeled antigen. There are two most common methods of separation:
    1. To the reaction mixture is added a substance that increases its density, for example, polyethylene glycol.
    2. A substance with high molecular weight is added to the reaction mixture, which specifically binds to antibodies in the composition of immune complexes. To do this, use second antibodies or staphylococcal protein A.
  4. In both cases, immune complexes having a higher molecular weight than free antigens are precipitated by centrifugation and the radioactivity of the precipitate is measured.
  5. Determine the concentration of antigen in the sample using the calibration curve. For its construction, several standard calibration solutions are used with known concentrations of unlabeled antigen.

 

Many RIA variants have been developed. The technique described above is called liquid-phase RIA (all reagents are in a dissolved state). There is also a solid-phase RIA, in which antibodies are immobilized on a water-insoluble carrier, for example, polystyrene. A special kind of method is the immunoradiometric assay, which uses labeled antibodies rather than a labeled antigen.

 

The RIA principle also applies to other immunochemical and non-immunochemical methods of analysis. For example, in ELISA, instead of a radioactive isotope, enzymes are used as a label, and in immunofluorometric analysis, fluorescent substances are used. In non-immunochemical methods, the role of antibodies is played by reagents that specifically bind the analyte. These reagents can be hormone receptors or plasma protein binding. For example, purified TSH receptors are used in the radio-receptor assay of thyroid-stimulating and thyroid-blocking autoantibodies, and thyroxine-binding globulin is sometimes used to measure the level of free T4.

 

  1. Ultrasound examination of the thyroid gland: characteristics of the method, indications, determined ultrasound parameters, disadvantages of the method. (Radial Diagnostics of Endocrinology)

Ultrasound of the thyroid gland – is one of the methods of investigation of the thyroid gland, which allows us to estimate its size and reveal the presence of some of the structural changes observed in diseases of the thyroid gland (goiter, tumors of the thyroid gland, thyroid adenoma, etc.). The thyroid gland is scanned in the cross-sectional plane, in the anteroposterior direction (the resulting picture differs from the “butterfly” shape, which is presented in anatomy textbooks and in isotope images).

  • Ultrasound anatomy: the trachea is defined directly behind the thyroid gland. The esophagus is defined posteriorly and to the left of the trachea and posteriorly to the left lobe of the thyroid gland. Major blood vessels in the neck run posteriorly and laterally to the lobes of the thyroid gland. Normal picture: the thyroid gland is covered with a capsule, which is clearly demarcated from the surrounding tissue. It has a granular homogeneous echo structure and is hypoechoic about the surrounding muscles.Normal dimensions: length 40-70 mm, width 10-30 mm, depth 10-20 mm (for each lobe). The isthmus is less than 5 mm wide.
  • Total volume: <25 ml for men, <20 ml for women.
  • Measurement of volume:
    • length
    • width
    • depth
    • 5 (for the lobe of the thyroid gland).
  • Normally, the thyroid gland on a longitudinal sonogram looks like a formation with a homogeneous structure and fairly clear contours. Both lobes of the gland are visible, each oval in shape, with clear contours and a granular, isoechoic structure. The isthmus of the gland is visualized as a linear formation up to 1 cm thick. Between the lobes, it is sometimes possible to distinguish between the cartilage of the larynx and the image of large vascular trunks. On transverse sections, the lateral borders of the thyroid gland are the common carotid artery and the internal jugular vein, which are visible as echo-negative formations of a round shape.

 

  1. The ultrasound picture of the thyroid gland is normal. (Radial Diagnostics of Endocrinology)

During ultrasound of the thyroid gland, a high-frequency ultrasonic sensor is installed above it and the reflected signals are displayed as an image on the monitor screen. Normal picture. Normally, the thyroid tissue is homogeneous on ultrasound.

Deviation from the norm. Cysts look like anechoic formations with smooth walls. With adenomas and thyroid cancer, either solid formations with clear boundaries and homogeneous echo signals are detected, or, which is less common, solid formations with cystic areas. Infiltrating thyroid cancer can be blurred. To identify the tumor, they resort to fine-needle or excisional biopsy.

 

  1. Radionuclide study of the intrathyroidal stage of iodine metabolism. Test-capture of iodine. (Radial Diagnostics of Endocrinology)

Investigation of intrathyroidal iodine metabolism The intrathyroidal stage of iodine metabolism consists of two phases: inorganic (capture of iodides from the blood) and organic (formation of thyroid hormones). For a summary assessment of this stage, the subject is given on an empty stomach a solution of 1311 sodium iodide in water with an activity of 100-150 kBq or 1231 with an activity of 500 kBq. Gamma radiation of iodine is recorded using a single-channel scintillation device, the sensor of which is located 30 cm from the anterior surface of the neck (Fig. 6.1) Under such geometric conditions of radiometry, the measurement results are almost not affected by the depth of the gland and its unequal thickness in different parts. Measurements of the radiation intensity over the thyroid gland are made 2, 24, and 72 hours after the reception of the RFP. The results obtained are compared with the total activity of the radioiodine introduced into the body, taken as 100%. This activity is determined by radiometry under the same geometric conditions of the same amount of RFP contained in the phantom. A glass or plastic model of the thyroid gland containing a precisely dosed solution of iodine radionuclide is used as a phantom.

Radioactive iodine uptake test The radioactive iodine uptake test can be done in parallel with thyroid scintigraphy. The study is contraindicated in pregnancy and breastfeeding. the test consists of two parts and is carried out over two days. On the first day, a radioactive isotope of iodine (usually 131I or 123I) is taken orally as a solution or in a capsule.
The determination of the degree of absorption is carried out after 4-6 hours, and then the next day – 24 hours after the intake of the isotope. In this case, a special device (scintillation counter) is placed at a distance of several centimeters from the front of the neck.
Determination of the volume of circulating blood The radioisotope method for determining the volume of circulating blood consists in the introduction into the blood of labeled with isotopes of phosphorus, carbon, bromine, or iodine of the patient’s own erythrocytes or erythrocytes of a universal donor (Rh-negative erythrocytes of group I (O)). The mass of circulating blood is determined by the degree of dilution of the radioactive preparation.

 

  1. Radionuclide study of the transport-organic stage of iodine exchange. (Radial Diagnostics of Endocrinology)

All tests of radio competitive analysis characterize the transport-organic stage of iodine metabolism. These include the determination of total tri-iodothyronine (TZ) and thyroxine (T4), free fractions of triiodothyronine and thyroxine (STZ, CT4), the thyroxine-binding capacity of blood serum (TCC), thyroxine-binding globulin (TSH), thyroglobulin (TG), antibodies to thyroglobulin (ATG), also, for the differential diagnosis of hypothyroid conditions, the content of hormones of other endocrine glands is determined: thyroid-stimulating hormone (TSH) of the pituitary gland, thyroliberin (TL) of the hypothalamus.
Determination of T4 allows more accurate determination of hypo- and hyperthyroid states than the capture of iodine. The test is used to monitor the treatment carried out in hyperthyroidism, for the differential diagnosis of thyroiditis, autonomic adenoma. The level of total thyroxine is influenced by the content of TSH (normally 20 μg / l) in the blood serum. With an increase in TSH, the content of T4 increases, with a decrease in the level of TSH, the concentration of T4, determined by the radioimmunoassay method, decreases. An increase in thyroxine-binding globulins and, accordingly, total thyroxine is observed during pregnancy, in the initial phase of acute hepatitis, estrogen therapy (including the use of oral contraceptives). A decrease in TSH occurs when taking certain medications (salicylates, promo, testosterone, anabolic steroids).

 

  1. Radiological methods of research of the adrenal glands: opportunities, advantages. (Radial Diagnostics of Endocrinology)

The adrenal glands are a paired organ of internal secretion. They are located in the retroperitoneal space above the kidneys at the level of the XI-XII vertebrae. Currently, the adrenal glands are studied by ultrasound and CT, and MRI.

The adrenal glands, in the absence of pathological signs, are visualized using ultrasound as triangular or oblong formations located anteriorly and medially about the upper pole of the kidney. The right adrenal gland is located between the upper pole of the kidney, the edge of the liver, and the diaphragm, the left adrenal gland is located between the upper pole of the kidney, the spleen, and the diaphragm. The echogenicity of the adrenal glands, as a rule, is higher than the echogenicity of the surrounding organs and tissues. On computed tomograms or MR tomograms, unchanged adrenal glands are defined as soft tissue formations located above the upper poles of the kidneys. Their shape is quite variable, but most often it is triangular or linear. An important advantage of CT in comparison with sonography is the possibility of densitometric analysis of normal and altered parts of the organ.

MRI also provides important additional information about the tissue characteristics of the adrenal glands. With this study, it is possible to differentiate the cortex and medulla of the normal adrenal glands. High tissue contrast, the absence of radiation exposure make it possible to give preference to MRI over other methods of examining the adrenal glands, especially in children. Adrenal scintigraphy is used relatively rarely since it is seriously inferior in informational content to CT and MRI. It is most commonly used when adrenal chromaffin tumors are suspected. especially in children. Adrenal scintigraphy is used relatively rarely since it is seriously inferior in informational content to CT and MRI. It is most commonly used when adrenal chromaffin tumors are suspected. especially in children. Adrenal scintigraphy is used relatively rarely since it is seriously inferior in informational content to CT and MRI. It is most commonly used when adrenal chromaffin tumors are suspected.

 

  1. Imaging radionuclide methods for studying endocrine glands. (Radial Diagnostics of Endocrinology)

scintigraphy is based on the use of radiopharmaceuticals. These substances contain radioactive elements that can be tracked with a special device. Once in the bloodstream, they are distributed in the body. At the same time, a characteristic feature of their distribution is the ability to selectively accumulate in certain organs, tissues, foci of the pathological process. To study the function of the thyroid gland, a radionuclide study is used. To obtain the correct test result, it is necessary to exclude the intake of iodine preparations for a month, so as not to block the gland. A radiopharmaceutical preparation containing technetium is administered intravenously. After that, scintigraphy of the gland is performed.

On the scintigram, the thyroid gland has an irregular shape, reminiscent of a “butterfly”, clear convex contours. The lobes and isthmus are usually clearly visible. The right lobe, as a rule, is somewhat larger than the left, although the position of the gland and its size is very variable. The density of scintillations in the central parts of the lobes is higher than in the periphery since most of the glandular tissue is located there. To visualize the thyroid gland, thyroid-stimulating drugs are used, mainly l23I, 13tI, and Tc-pertechnetate. The scan is a planar image of the thyroid gland, reflecting its position, shape, size, and, to a certain extent, the functional state of a nuclide localized in the gland. Functional activity of thyroid tissue glands is determined by the intensity of shading or the nature of the color (on color scanners). In practical terms, it is extremely important.

adrenal scintigraphy – allows you to obtain valuable diagnostic information if the patient has adrenal neoplasms, adrenal hyperplasia, primary hyperaldosteronism, Cushing’s syndrome; – Scintigraphy of the adrenal medulla is performed to diagnose pheochromocytoma.

Requires special preparation for research during 1 week.

The study is carried out in several stages: after 4-6 hours, 17-24 hours, and 40-48 hours after the injection.

parathyroid scintigraphy– prescribed for suspected adenoma, carcinoma, hyperplasia, or malformations of the parathyroid glands; SCYNTIGRAPHY OF PARATHYROID GLANDS. Scintigraphic imaging of the pathologically altered parathyroid glands is based on the accumulation of diagnostic radiopharmaceuticals by their tissue, which exhibits increased affinity for tumor cells. The detection of enlarged parathyroid glands is carried out by comparing scintigraphic images obtained with the maximum accumulation of the radiopharmaceutical in the thyroid gland (thyroid phase of the study) and with its minimum content in the thyroid gland with the maximum accumulation in the pathologically altered parathyroid glands (parathyroid phase of the study).

 

  1. Radionuclide methods for studying the function of endocrine glands. (Radial Diagnostics of Endocrinology)

Notice not radioactive isotopes, but substances or compounds labeled with radionuclides. Strictly speaking , radiopharmaceuticals (RFP) = carrier + label (radionuclide) are administered. This method allows you to study the processes of hormone synthesis in the endocrine tissue, the deposition, and distribution of hormones in the body, the ways of their excretion. It is customary to divide radionuclide methods into in vivo and in vitro studies. In vivo studies distinguish between in vivo and in vitro measurements. First of all, all methods can be divided into in vitro and in vivo studies (methods, diagnostics). In vitro studies. In vitro and in vivo studies (methods) should not be confused with the concept of in vitro and in vivo measurements. In vivo – measurements will always be in vivo- research. Those. cannot be measured in the body, something that was not (substance, parameter) or was not introduced as a testing agent in the study. If a test substance was introduced into the body, then a bioassay was taken and in vitro measurements were carried out, the study should still be designated as an in vivo study. If the test substance was not injected into the body, but a biological sample was taken and carried out in vitro – measurements, with the introduction or without the introduction of a test substance (reagent for example), the study should be designated as an in vitro study.

In in vivo radionuclide diagnostics, the capture of RP from the blood by endocrine cells is more often used and is included in the resulting hormones in proportion to the intensity of their synthesis. An example of using this method is the study of the thyroid gland using radioactive iodine (131I) or sodium pertechnetate (Na99mTcO4), the adrenal cortex using a labeled precursor of steroid hormones, most often cholesterol (131I – cholesterol). When the radionuclide in vivo studies performed radiometry or gamma -topography (scintigraphy). Radionuclide scanning is obsolete as a method.

Separate assessment of inorganic and organic phases of the intrathyroidal stage of iodine metabolism. In the study of hormonal regulation of self-loops at Vivo – studies apply stimulation and suppression tests. To study the sites of binding, accumulation, and metabolism of hormones, they are labeled with the help of radioactive atoms, injected into the body, and autoradiography is used. Sections of the studied tissues are placed on a radiosensitive photographic material, such as an X-ray film, and the places of darkening are compared with photographs of histological sections.

Study of the content of hormones in bioassays.          Most often, blood (plasma, serum) and urine are used as bioassays. This method is one of the most accurate for assessing the secretory activity of endocrine organs and tissues, but it does not characterize the biological activity and the degree of hormonal effects in tissues. Various research methods are used depending on the chemical nature of hormones, including biochemical, chromatographic, and biological testing methods, and again radionuclide methods. Among the radionuclide meds distinguish radioimmunoassay (RIA) immunoradiometric (IRMA) radioreceptor (PPA) In 1977, Rosalyn Yalow received the Nobel Prize for improved methods of radioimmunoassay (RIA) of peptide hormones. Radioimmunoassay, which is most widely used today due to its high sensitivity, accuracy, and simplicity, is based on the use of isotopes labeled with iodine (125I) or tritium (3H) hormones and specific antibodies that bind them. Why is it needed? A lot of blood sugar In most diabetic patients, insulin activity in the blood is rarely reduced, more often it is normal or even increased. The second example is hypocalcemia. Parathyrin is often elevated. Radionuclide methods make it possible to determine the fractions (free, bound to proteins) of hormones. In a radioreceptor assay, the sensitivity of which is lower, and the informativeness is higher than that of a radioimmune assay, the binding of the hormone not to antibodies to it, but to specific hormonal receptors of cell membranes or cytosol, is assessed.

When studying the contours of self-regulation of hormonal regulation in vitro-studies use the definition of a complete “set” of hormones of various levels of regulation associated with the process under study (liberins and statins, tropins, effector hormones). For example, for the thyroid gland, thyroliberin, thyrotropin, triiodothyronine, thyroxine. Relative specificity of regulation: the introduction of iodine and dioidtyrosine inhibits the production of thyrotropin. Comparison of the physiological activity of the blood flowing to the organ and outflowing from it makes it possible to reveal the secretion of biologically active metabolites and hormones into the blood. Investigation of the content of precursors of synthesis and metabolites of hormones in the blood and urine.

Often, the hormonal effect is largely determined by the active metabolites of the hormone. In other cases, precursors of synthesis and metabolites, the concentration of which is proportional to the levels of the hormone, are more readily available for research. The method allows not only to assess the hormone-producing activity of endocrine tissue but also to reveal the features of hormone metabolism. Observation of patients with impaired function of endocrine organs… This can provide valuable information about the physiological effects and the role of endocrine hormones. Addison T. (Addison Tomas), English physician (1793-1860). He is called the father of endocrinology. In 1855 he published a monograph containing, in particular, the classic description of chronic adrenal insufficiency. Soon it was proposed to call it Addison’s disease. The cause of Addison’s disease is most often a primary lesion of the adrenal cortex by an autoimmune process (idiopathic Addison’s disease) and tuberculosis.

 

  1. Indications for the study of the thyroid gland. 

Metabolic disorders, clinical signs of hypo- and hyperthyroidism, planned to the image of the thyroid gland. If during the examination there are palpatory changes in the structure of the gland (for example, the appearance of seals or nodes), then he will send the patient to the ultrasound diagnostics room for further examination. Examine the condition of the gland by ultrasound should also in the following cases: if the blood test revealed abnormalities in the hormonal activity of the gland; the appearance of a feeling of suffocation, a feeling of “coma” in the throat; the appearance of mood swings (nervousness, irritability, insomnia); marked weight loss over a fairly short period of time; the presence of low-grade body temperature for a long time.

 

  1. Principles of complex diagnostics of thyroid diseases.

The general condition of the patient is assessed, attention is drawn to the expression of fear on the face, fussiness, tearfulness, verbosity, irrational movements, trembling of outstretched arms. Height, weight, and body temperature are noted. The skin of patients with toxic goiter is warm, moist, with normal turgor. Sometimes there is hyperpigmentation of the skin, induration on the front surface of the lower leg, brittle hair, and baldness. Subcutaneous adipose tissue is moderately developed, and significant weight loss is often noted. When examining the neck area, attention is paid to the enlargement of the thyroid gland. The goiter can be diffuse, mixed, and nodular, of varying density and degree of enlargement.

There are several degrees of magnification:

  1. 0 degree – no goiter
  2. Grade 1 – a goiter is palpable the size of the distal phalanx of the thumb
  3. 2 degree – the gland is palpable and visible to the eye.

The isthmus is palpable when swallowing. If the sternocleidomastoid muscle is strongly developed, the patient should be asked to lean forward. When the muscles are relaxed, both lobes are palpated. With a low position, the thyroid gland is examined during swallowing or in the position of the patient lying on his back with an extended neck. It should be borne in mind that the degree of thyroid enlargement does not determine the severity of the toxic goiter.

Then the eye symptoms are assessed, the time of the onset of exophthalmos is specified and compared with the development of other symptoms of the disease. An important indicator of the functional state of the thyroid gland is blood pressure. It should be measured two or three times, paying attention to the value of the arterial pulse pressure, which, as a rule, with thyrotoxicosis, is significantly increased, both due to an increase in systolic and a decrease in diastolic. Attention is also paid to the sonority of heart sounds, the presence of murmurs and the place of hearing them, as well as the nature of the conduct, which is important for the differential diagnosis of the disease.

 

Additional research. In patients with diffuse toxic goiter, iron deficiency anemia, leukopenia, lymphocytosis, and a slight increase in ESR are determined. At the same time, hypoalbuminemia, hypergammaglobulinemia, hypocholesterolemia, hypokalemia, hypernatremia, hypomagnesemia are observed. The most important diagnostic value is an increase in the iodine storage function of the thyroid gland, the content of total thyroxine in the blood, as well as the state of basic metabolism.

 

  1. Stages of iodine exchange.

Radionuclide techniques play a leading role in the study of iodine metabolism and in the diagnosis of thyroid diseases. The process of iodine metabolism in the body is very complex and includes inorganic, intrathyroidal, transport-organic, and peripheral (tissue) stages of iodine metabolism. Therefore, it cannot be studied using any one methodology. A complete radiological examination consists of a set of tests that assess all stages of iodine metabolism.

 

  1. Radiometry of the thyroid gland: possibilities, methods, and principles of evaluation of results.

Hypothyroidism is accompanied by a decrease in the absorption of iodine-131 by the thyroid gland, mainly after 24-72 hours (at a rate of 25-50%, the indicators do not exceed 10-15%). However, it should be noted that the use of radiometry is more appropriate and informative in the diagnosis of hyperthyroidism than hypothyroidism.

In some cases, the absorption of labeled triiodothyronine by erythrocytes is determined. In patients with hypothyroidism, this figure decreases to 8% or less.

 

 

  1. The functional states of the thyroid gland determined by radionuclide research.

The saturation of the thyroid tissue with a radioisotope is assessed in the image by the background density (darker-lighter) or color. If against the general background, any area (gland) differs in excessive or insufficient saturation of color or in another color, then this indicates an excessive or insufficient saturation with a radioactive isotope. Or, in other words, about the magnitude of the activity of the thyroid tissue site. To designate such areas, doctors use terms related to temperature: cold or hot focus. It is not easy to explain why, while studying the radioisotope activity of the gland tissue, experts use the unsuitable category – temperature. Nevertheless, this traditional designation is generally accepted and understood.

Cold and Hot

During unstressed work, the tissue of the thyroid gland should be uniformly saturated with a radioisotope, and look like two darker almost oval areas on the scan.

Bleaching in the area of ​​one of these areas is usually regarded as insufficient saturation with the isotope and is called a cold focus. Darker areas within one of the specified oval areas (ie, the lobes of the thyroid gland) are called hot or warm foci.

It is not uncommon for patients to be preliminarily examined using ultrasound before being sent for a radioisotope scan. If nodules are detected in the thyroid gland, then the main attention during scanning is given to the functional assessment of these nodes. Therefore, depending on the activity of the capture of radioactive substances, doctors may not talk about foci, but about hot or cold nodes.

Depending on the isotope used, the same node in the thyroid gland can be hot or cold. For example, sometimes a focal lesion when scanning with technetium-99t pertechnetate is perceived as a warm (hot) area. A subsequent scan using the radioisotope 123 iodine presents this node as cold.

Since iodine is considered the main guideline in diagnostics, in the case of detected changes during scanning with the technetium isotope, some specialists suggest a repeated examination using the iodine isotope.

 

  1. methods of radiation diagnostics of parathyroid gland diseases. (Radial Diagnostics of Endocrinology)

Imaging of the thyroid gland can be used by a variety of methods, including ultrasonography (US), scintigraphy, CT. MRI. Each technique has its own advantages and disadvantages and has different diagnostic sensitivity and specificity.

Ultrasound examination In typical cases, the parathyroid gland sonographically represents formations of a round or oval shape, less than 3 cm in size in any direction, with smooth clear contours, hypoechoic, more often of a homogeneous structure, located at the posterior wall of the upper and lower poles of the thyroid gland

scintigraphyThe principle of the protocol using two labels is based on the fact that two isotopes are sequentially injected into a vein, after each injection a picture is taken. Since the elimination of the isotope from the thyroid and parathyroid glands occurs at different rates (slower from the parathyroid gland), when subtracting the image obtained using the second label, which accumulates only in the thyroid gland, the desired image of the hyper-functional parathyroid glands is obtained from the first image.

contrast-enhanced computed tomography allows a fairly accurate assessment of the size and localization of the thyroid gland, both in the case of their normal number and location and in the presence of additional thyroid glands and their ectopia, including in the mediastinum.

Magnetic resonance imaging (MRI), like CT, is a good method for imaging the thyroid gland.

 

  1. Methods of radial diagnostics of diseases of the pituitary gland. (Radial Diagnostics of Endocrinology)

Computed tomography of the pituitary gland (Radial Diagnostics of Endocrinology), along with MRI, is the leading method for visualizing pituitary adenomas (prolactinomas, somatotropinomas, prolactocorticotropinomas, prolactosomatotropinomas), as well as hormonally inactive (“silent”) tumors. CT scan of the pituitary gland assesses the topography, size, glands; the presence of additional formations, their size and structure (solid, cystic), spread beyond the Turkish saddle, germination into bone structures, and hard shells of the brain. When performing a CT scan of the pituitary gland, it is advisable to use high resolution and contrast enhancement. MRI of the pituitary gland is the main method for diagnosing adenomas and allows you to identify the tumor, assess its size and relationship with the chiasma and optic nerves. MRI is practically the only method to detect pituitary microadenomas because their size is very small.

 

  1. Ultrasound syndrome of diffuse thyroid damage: the main signs, diseases in which it occurs. (Radial Diagnostics of Endocrinology)

In Radial Diagnostics of Endocrinology, Diffuse toxic goiter ( disease Basedow, Disease Graves’ disease) – a disease caused by hypertrophy and hyperfunction of the thyroid gland, accompanied by the development of hyperthyroidism. Clinically manifested by increased excitability, irritability, weight loss, palpitations, sweating, shortness of breath, low-grade fever.

With a diffuse increase in the thyroid gland, the structure of the gland changes: it becomes denser and increases in volume. In the early stages of diffuse enlargement of the thyroid gland, symptoms of such changes are usually absent. In this case, changes in the structure of the organ are ascertained when visiting an endocrinologist who examines and palpates the gland. After detecting abnormalities in the structure of the thyroid gland, the specialist prescribes a laboratory blood test to determine the hormonal status and the level of antibodies to the thyroid gland.

After laboratory tests (or in conjunction with them), an ultrasound examination (ultrasound) is prescribed to make a diagnosis and prescribe appropriate therapy.

The progression of thyroid disease leads not only to a change in the structure of the tissues of the gland but also to malfunctions of the whole organism. The very first “blow” is taken by the nervous system: a person becomes anxious and restless, as well as irritable and unbalanced. Then there are problems with the functioning of the heart and blood vessels, the activity of the reproductive system is disrupted. Metabolic processes in the body are also affected since thyroid hormones regulate calcium metabolism in the body. As a result, the patient may develop multiple caries and osteoporosis.

 

  1. Ultrasound syndrome of focal thyroid damage: the main signs, diseases in which it occurs. (Radial Diagnostics of Endocrinology)

Focal formations in the thyroid gland are not a disease, but an ultrasound sign of abnormalities in the normal tissues of the organ. When there is a pain in the neck area, its enlargement, difficulties with swallowing, a person turns to a therapist or endocrinologist. The doctor directs for an ultrasound examination, where focal or diffuse formations can be detected.
Benign tumors include:

  1. Nodes. Formed as a result of rapid and intense cell division. They can be single, multiple, calm, or toxic. A single knot is an elastic ball of dense consistency. Nodules are most common in endocrinological practice.
  2. Cysts. Revealed less often. The thyroid gland changes its size, becomes noticeably larger. When palpating, the doctor notes a soft seal.
  3. An adenoma is a ball with a fibrous capsule, characterized by slow growth.

Ultrasound is a more reliable method. Allows you to see the size of the thyroid gland, neoplasms, tissue structure, and also to suggest the nature of the lesion – benign or malignant. This method is successfully used for preventive examinations. It allows diagnosing even small nodal seals.

  1. Ultrasound syndrome of thyroid abnormality: the main signs and tactics of subsequent radiation examination. (Radial Diagnostics of Endocrinology)

In Radial Diagnostics of Endocrinology, During ultrasound of the thyroid gland, it is possible to determine the size of the thyroid gland, the structure of its tissues (including the presence of cysts, tumors, and nodes), the degree of tissue density, which is indicated by echogenicity.

The description of the thyroid gland normally looks something like this: “the thyroid gland is of normal shape, located correctly, its contours are even and clear, the echo structure is homogeneous, not changed, there are no nodes; the lymph nodes of the submandibular, subclavian and neck regions are not enlarged. ”

In the structure of the thyroid gland, diffuse (spread to the entire gland) and local (small areas), changes can be identified.

The thyroid gland is enlarged in all directions, including an enlarged isthmus. Typical ultrasound signs of thyroiditis are varying degrees of decrease in echogenicity of the gland tissue and diffuse (widespread throughout the gland) tissue heterogeneity – from fine-grained to much coarser. diffuse changes in the thyroid gland can also be with diffuse toxic goiter (Graves’ disease), they appear in the form of its uniform increase, sometimes two to three times compared with the norm. The structure of the gland tissue is usually homogeneous – normal or somewhat denser, with increased echogenicity. Sometimes, against the background of diffuse changes, secondary nodules, cysts, and deposits of calcium salts may appear.

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