Ultrasound diagnostic method is a method of obtaining a medical image based on registration and computer analysis of reflections from biological structures ultrasonic waves, i.e. based on the echo effect. The method is often called echography. Modern devices for ultrasound examination(ultrasound) are universal high-resolution digital systems with the ability to scan in all modes (Fig. 3.1).

Ultrasound diagnostic power is virtually harmless. Ultrasound has no contraindications, is safe, painless, atraumatic and not burdensome. If necessary, it can be performed without any preparation of patients. Ultrasound equipment can be delivered to any functional department for the examination of non-transportable patients. Great advantage, especially when it is unclear clinical picture, is the possibility of simultaneous examination of many organs. The great cost-effectiveness of echography is also important: the cost of ultrasound is several times less than X-ray studies, and even more so computed tomography and magnetic resonance imaging.

However, the ultrasonic method also has some disadvantages:

High hardware and operator dependence;

Greater subjectivity in the interpretation of echographic images;

Low information content and poor demonstrativeness of frozen images.

Ultrasound has now become one of the methods most commonly used in clinical practice. In recognizing diseases of many organs, ultrasound can be considered as the preferred, first and main diagnostic method. In diagnostically difficult cases, ultrasound data allows us to outline a plan for further examination of patients using the most effective radiation methods.

PHYSICAL AND BIOPHYSICAL BASICS OF ULTRASONIC DIAGNOSTIC METHOD

Ultrasound is called sound vibrations, lying above the threshold of perception by the human hearing organ, i.e., having a frequency of more than 20 kHz. Physical basis Ultrasound is the piezoelectric effect discovered in 1881 by the Curie brothers. His practical application associated with the development by Russian scientist S. Ya. Sokolov of ultrasonic industrial flaw detection (late 20s - early 30s of the twentieth century). The first attempts to use the ultrasound method for diagnostic purposes in medicine date back to the late 30s. XX century. Wide Application Ultrasound in clinical practice started in the 1960s.

The essence of the piezoelectric effect is that when single crystals of some chemical compounds(quartz, titanium, barium, cadmium sulfide, etc.), in particular, under the influence of ultrasonic waves, electric charges of opposite sign appear on the surfaces of these crystals. This is the so-called direct piezoelectric effect (piezo in Greek means to press). On the contrary, when an alternating electric charge is applied to these single crystals, mechanical vibrations arise in them with the emission of ultrasonic waves. Thus, the same piezoelectric element can alternately be a receiver and a source of ultrasonic waves. This part in ultrasound machines is called an acoustic transducer, transducer or sensor.

Ultrasound propagates in media in the form of alternating zones of compression and rarefaction of substance molecules that perform oscillatory movements. Sound waves, including ultrasonic ones, are characterized by a period of vibration - the time during which a molecule (particle) completes one complete vibration; frequency - the number of oscillations per unit time; length - the distance between points of one phase and the speed of propagation, which depends mainly on the elasticity and density of the medium. The length of a wave is inversely proportional to its frequency. The shorter the wavelength, the higher the resolution of the ultrasonic device. Medical ultrasound diagnostic systems typically use frequencies from 2 to 10 MHz. The resolution of modern ultrasonic devices reaches 1-3 mm.

Any environment, including various tissues of the body, prevents the propagation of ultrasound, i.e., it has different acoustic resistance, the value of which depends on their density and the speed of ultrasound. The higher these parameters, the greater the acoustic resistance. Such general characteristics any elastic medium is designated by the term “impedance”.

Having reached the boundary of two media with different acoustic resistance, the beam of ultrasonic waves undergoes significant changes: one part of it continues to propagate in the new medium, being absorbed to one degree or another by it, the other is reflected. The reflection coefficient depends on the difference in the acoustic resistance of tissues adjacent to each other: the greater this difference, the greater the reflection and, naturally, the greater the amplitude of the recorded signal, which means the lighter and brighter it will appear on the device screen. A complete reflector is the boundary between tissue and air.

ULTRASONIC RESEARCH METHODS

Currently, ultrasound in B- and M-mode and Doppler ultrasound are used in clinical practice.

B-mode is a technique that provides information in the form of two-dimensional gray-scale tomographic images of anatomical structures in real time, which allows one to assess their morphological state. This mode is the main one; in all cases, ultrasound begins with its use.

Modern ultrasonic equipment captures the smallest differences in the levels of reflected echo signals, which are displayed in many shades gray. This makes it possible to differentiate anatomical structures, even slightly different from each other in acoustic resistance. The lower the echo intensity, the darker the image, and, conversely, the greater the energy of the reflected signal, the brighter the image.

Biological structures can be anechoic, hypoechoic, medium echogenic, hyperechoic (Fig. 3.2). An anechoic image (black) is characteristic of formations filled with liquid, which practically does not reflect ultrasonic waves; hypoechoic (dark gray) - tissues with significant hydrophilicity. An echo-positive image (gray) is produced by most tissue structures. Dense biological tissues have increased echogenicity (light gray in color). If ultrasonic waves are completely reflected, then objects appear hyperechoic (bright white), and behind them there is a so-called acoustic shadow, which looks like a dark path (see Fig. 3.3).

a b c d e

Rice. 3.2. Scale of levels of echogenicity of biological structures: a - anechoic; b - hypoechoic; c - medium echogenicity (echopositive); d - increased echogenicity; d - hyperechoic

Rice. 3.3. Echograms of the kidneys in a longitudinal section with the designation of various structures

echogenicity: a - anechoic dilated pyelocaliceal complex; b - hypoechoic renal parenchyma; c - liver parenchyma of medium echogenicity (echopositive); d - renal sinus of increased echogenicity; d - hyperechoic stone in the ureteropelvic segment

Real-time mode provides a “live” image of organs and anatomical structures in their natural functional state on the monitor screen. This is achieved by the fact that modern ultrasound machines produce many images following each other at intervals of hundredths of a second, which in total creates a constantly changing picture that records the slightest changes. Strictly speaking, this technique and the ultrasound method in general should be called not “echography”, but “echoscopy”.

M-mode - one-dimensional. In it, one of the two spatial coordinates is replaced by a time one, so that the distance from the sensor to the located structure is plotted along the vertical axis, and time is plotted along the horizontal axis. This mode is mainly used for cardiac examination. It provides information in the form of curves reflecting the amplitude and speed of movement of cardiac structures (see Fig. 3.4).

Dopplerography is a technique based on the use of the physical Doppler effect (named after the Austrian physicist). The essence of this effect is that ultrasonic waves are reflected from moving objects with a changed frequency. This frequency shift is proportional to the speed of movement of the located structures, and if their movement is directed towards the sensor, the frequency of the reflected signal increases, and, conversely, the frequency of waves reflected from the receding object decreases. We encounter this effect all the time, observing, for example, changes in the frequency of sound from cars, trains, and planes rushing past.

Currently, in clinical practice, flow spectral Doppler, color Doppler mapping, power Doppler, convergent color Doppler, three-dimensional color Doppler mapping, and three-dimensional power Doppler are used to varying degrees.

Streaming spectral Dopplerography designed to assess blood flow in relatively large

Rice. 3.4. M - modal curve of movement of the anterior mitral valve leaflet

vessels and chambers of the heart. The main type of diagnostic information is a spectrographic record, which is a sweep of blood flow velocity over time. On such a graph, speed is plotted along the vertical axis, and time is plotted along the horizontal axis. Signals displayed above the horizontal axis come from the blood flow directed towards the sensor, below this axis - from the sensor. In addition to the speed and direction of blood flow, by the type of Doppler spectrogram, the nature of the blood flow can also be determined: laminar flow is displayed as a narrow curve with clear contours, turbulent flow is displayed as a wide heterogeneous curve (Fig. 3.5).

There are two options for flow Doppler ultrasound: continuous (constant wave) and pulsed.

Continuous Doppler ultrasonography is based on the constant emission and constant reception of reflected ultrasound waves. In this case, the magnitude of the frequency shift of the reflected signal is determined by the movement of all structures along the entire path of the ultrasonic beam within the depth of its penetration. The information obtained is thus summary. The impossibility of isolated analysis of flows in a strictly defined location is a disadvantage of continuous Dopplerography. At the same time, it also has an important advantage: it allows the measurement of high blood flow rates.

Pulsed Dopplerography is based on the periodic emission of a series of pulses of ultrasonic waves, which, reflected from red blood cells, sequentially perceive

Rice. 3.5. Doppler spectrogram of transmitral blood flow

with the same sensor. In this mode, signals reflected only from a certain distance from the sensor are recorded, which is set at the discretion of the doctor. The place where blood flow is studied is called the reference volume (CV). Possibility of assessing blood flow at any time given point is the main advantage of pulsed Dopplerography.

Color Doppler mapping based on color coding of the Doppler shift value of the emitted frequency. The technique provides direct visualization of blood flow in the heart and in relative large vessels(see Fig. 3.6 on the color insert). Red color corresponds to the flow going towards the sensor, blue - from the sensor. The dark shades of these colors correspond low speeds, light shades - high. This technique allows you to assess both the morphological state of blood vessels and the state of blood flow. A limitation of the technique is the inability to obtain images of small blood vessels with low blood flow speed.

Power Dopplerography is based on the analysis not of frequency Doppler shifts, reflecting the speed of movement of red blood cells, as with conventional Doppler mapping, but of the amplitudes of all echo signals of the Doppler spectrum, reflecting the density of red blood cells in a given volume. The resulting image is similar to conventional color Doppler mapping, but differs in that all vessels are imaged regardless of their path relative to the ultrasound beam, including blood vessels of very small diameter and with low blood flow velocity. However, it is impossible to judge the direction, character, or speed of blood flow from power Dopplerograms. Information is limited only by the fact of blood flow and the number of vessels. Shades of color (as a rule, with a transition from dark orange to light orange and yellow) convey information not about the speed of blood flow, but about the intensity of echo signals reflected by moving elements of the blood (see Fig. 3.7 on the color insert). The diagnostic value of power Dopplerography lies in the ability to assess the vascularization of organs and pathological areas.

The capabilities of color Doppler mapping and power Doppler are combined in the technique convergent color dopplerography.

The combination of B-mode with flow or energy color mapping is designated as a duplex study, which provides the greatest amount of information.

3D Doppler and 3D Power Doppler - these are techniques that make it possible to observe a three-dimensional picture of the spatial location blood vessels in real time from any angle, which makes it possible to accurately assess their relationship with various anatomical structures and pathological processes, including malignant tumors.

Echo contrast. This technique is based on the intravenous administration of special contrast agents containing free gas microbubbles. To achieve clinically effective contrast enhancement, the following prerequisites are required. At intravenous administration With such echo contrast agents, only those substances that freely pass through the capillaries of the pulmonary circulation can enter the arterial bed, i.e., gas bubbles should be less than 5 microns. Second prerequisite is the stability of gas microbubbles during their circulation in the general vascular system at least 5 min.

In clinical practice, the echo contrast technique is used in two directions. The first is dynamic echo-contrast angiography. At the same time, visualization of blood flow is significantly improved, especially in small, deeply located vessels with low blood flow velocity; the sensitivity of color Doppler mapping and power Doppler sonography is significantly increased; provides the ability to observe all phases of vascular contrast in real time; the accuracy of assessing stenotic lesions of blood vessels increases. The second direction is tissue echo contrast. It is ensured by the fact that some echocontrast substances are selectively included in the structure of certain organs. Moreover, the degree, speed and time of their accumulation in unchanged and pathological tissues are different. Thus, in general, it becomes possible to assess organ perfusion, improving contrast resolution between normal and diseased tissue, which helps to increase the accuracy of diagnosis of various diseases, especially malignant tumors.

The diagnostic capabilities of the ultrasound method have also expanded due to the emergence of new technologies for obtaining and post-processing of echographic images. These include, in particular, multi-frequency sensors, technologies for forming wide-format, panoramic, and three-dimensional images. Promising directions further development of the ultrasound diagnostic method is the use of matrix technology for collecting and analyzing information about the structure of biological structures; creation of ultrasound devices that provide images of full sections of anatomical areas; spectral and phase analysis of reflected ultrasonic waves.

CLINICAL APPLICATION OF ULTRASONIC DIAGNOSTIC METHOD

Ultrasound is currently used in many areas:

Planned studies;

Emergency diagnostics;

Monitoring;

Intraoperative diagnostics;

Postoperative studies;

Monitoring the implementation of diagnostic and therapeutic instrumental manipulations (punctures, biopsies, drainage, etc.);

Screening.

Emergency ultrasound should be considered the first and mandatory method instrumental examination patients with acute surgical diseases of the abdominal and pelvic organs. At the same time, the diagnostic accuracy reaches 80%, the accuracy of recognizing damage to parenchymal organs is 92%, and the detection of fluid in the abdominal cavity (including hemoperitoneum) is 97%.

Monitoring ultrasounds are performed repeatedly at different intervals during the acute pathological process to assess its dynamics, the effectiveness of the therapy, early diagnosis complications.

The goals of intraoperative studies are to clarify the nature and extent of the pathological process, as well as to monitor the adequacy and radicality of surgical intervention.

Ultrasound in early dates after surgery are aimed mainly at establishing the cause of the unfavorable course of the postoperative period.

Ultrasound control over the performance of instrumental diagnostic and therapeutic manipulations ensures high accuracy of penetration to certain anatomical structures or pathological areas, which significantly increases the effectiveness of these procedures.

Screening ultrasounds, i.e. studies without medical indications, are carried out for the early detection of diseases that have not yet manifested themselves clinically. The feasibility of these studies is evidenced, in particular, by the fact that the frequency of newly diagnosed diseases of the abdominal organs during screening ultrasound of “healthy” people reaches 10%. Excellent results in the early diagnosis of malignant tumors are obtained by screening ultrasound of the mammary glands in women over 40 years of age and of the prostate in men over 50 years of age.

Ultrasounds can be performed by either external or intracorporeal scanning.

External scanning (from the surface of the human body) is the most accessible and completely unburdensome. There are no contraindications to its implementation; there is only one general limitation - the presence of a wound surface in the scanning area. To improve the contact of the sensor with the skin, its free movement across the skin and to ensure the best penetration of ultrasonic waves into the body, the skin at the test site should be generously lubricated with a special gel. Scanning of objects located at different depths should be carried out with a certain radiation frequency. Thus, when studying superficially located organs (thyroid gland, mammary glands, soft tissue structures of joints, testicles, etc.), a frequency of 7.5 MHz and higher is preferable. To study deep-lying organs, sensors with a frequency of 3.5 MHz are used.

Intracorporeal ultrasound is carried out by introducing special sensors into the human body through natural openings (transrectal, transvaginal, transesophageal, transurethral), puncture into vessels, through surgical wounds, and also endoscopically. The sensor is brought as close as possible to a particular organ. In this regard, it becomes possible to use high-frequency transducers, due to which the resolution of the method sharply increases, and it becomes possible to high-quality visualize the smallest structures that are inaccessible with external scanning. For example, transrectal ultrasound, compared with external scanning, provides important additional diagnostic information in 75% of cases. The detection rate of intracardiac thrombi with transesophageal echocardiography is 2 times higher than with external examination.

The general patterns of formation of an echographic gray scale image are manifested by specific patterns characteristic of a particular organ, anatomical structure, pathological process. In this case, their shape, size and position, the nature of the contours (smooth/uneven, clear/fuzzy), internal echo structure, displacement, and for hollow organs (gall and bladder), in addition, the condition of the wall (thickness, echo density, elasticity) must be assessed ), the presence of pathological inclusions in the cavity, primarily stones; degree of physiological contraction.

Cysts filled serous fluid, are displayed in the form of rounded, uniformly anechoic (black) zones, surrounded by an echopositive (gray) rim of the capsule with smooth, clear contours. A specific echographic sign of cysts is the effect of dorsal enhancement: back wall the cyst and the tissue behind it look lighter than the rest of the area (Fig. 3.8).

Cavity formations with pathological contents (abscesses, tuberculous cavities) differ from cysts in the unevenness of their contours and, most importantly, the heterogeneity of the echo-negative internal echostructure.

Inflammatory infiltrates are characterized by an irregular round shape, unclear contours, and evenly and moderately reduced echogenicity of the pathological process area.

The echographic picture of hematoma of parenchymal organs depends on the time that has passed since the injury. In the first few days it is homogeneously echo-negative. Then echo-positive inclusions appear in it, which are a reflection of blood clots, the number of which is constantly increasing. After 7-8 days, the reverse process begins - lysis of blood clots. The contents of the hematoma again become uniformly echo-negative.

The echostructure of malignant tumors is heterogeneous, with zones of the entire spectrum

Rice. 3.8. Sonographic image of a solitary renal cyst

echogenicity: anechoic (hemorrhage), hypoechoic (necrosis), echopositive (tumor tissue), hyperechoic (calcification).

The echographic picture of the stones is very demonstrative: a hyperechoic (bright white) structure with an acoustic echo-negative dark shadow behind it (Fig. 3.9).

Rice. 3.9. Sonographic image of gallstones

Currently, ultrasound is available to almost all anatomical areas, organs and anatomical structures of a person, although to varying degrees. This method is a priority in assessing both the morphological and functional state of the heart. Its informative value is also high in the diagnosis of focal diseases and damage to the parenchymal organs of the abdomen, diseases of the gallbladder, pelvic organs, external male genitalia, thyroid and mammary glands, and eyes.

INDICATIONS FOR Ultrasound

Head

1. Brain research in children early age, mainly if a congenital disorder of its development is suspected.

2. Study of cerebral vessels in order to establish the causes of cerebrovascular accidents and to evaluate the effectiveness of vascular operations.

3. Eye examination for diagnosis various diseases and damage (tumors, retinal detachment, intraocular hemorrhages, foreign bodies).

4. Research salivary glands to assess their morphological state.

5. Intraoperative control of the total removal of brain tumors.

Neck

1. Study of the carotid and vertebral arteries:

Prolonged, frequently recurring severe headaches;

Frequently recurring fainting;

Clinical signs of cerebrovascular accidents;

Clinical subclavian steal syndrome (stenosis or occlusion of the brachiocephalic trunk and subclavian artery);

Mechanical trauma (vascular damage, hematoma).

2. Research thyroid gland:

Any suspicion of her illness;

3. Research lymph nodes:

Suspicion of their metastatic damage when a malignant tumor of any organ is detected;

Lymphomas of any localization.

4. Non-organ neoplasms of the neck (tumors, cysts).

Breast

1. Heart examination:

Diagnostics birth defects hearts;

Diagnosis of acquired heart defects;

Quantification functional state heart (global and regional systolic contractility, diastolic filling);

Assessment of the morphological state and function of intracardial structures;

Identification and establishment of the degree of disturbances of intracardiac hemodynamics (pathological shunting of blood, regurgitant flows due to insufficiency of the heart valves);

Diagnosis of hypertrophic myocardiopathy;

Diagnostics of intracardiac blood clots and tumors;

Revealing coronary disease myocardium;

Determination of fluid in the pericardial cavity;

Quantification of pulmonary arterial hypertension;

Diagnosis of heart damage due to mechanical trauma to the chest (bruises, ruptures of walls, septa, chords, valves);

Assessment of the radicality and effectiveness of heart surgery.

2. Examination of the respiratory organs and mediastinum:

Determination of fluid in the pleural cavities;

Clarification of the nature of the lesions chest wall and pleura;

Differentiation of tissue and cystic neoplasms mediastinum;

Assessment of the condition of the mediastinal lymph nodes;

Diagnosis of thromboembolism of the trunk and main branches of the pulmonary artery.

3. Examination of the mammary glands:

Clarification of uncertain radiological data;

Differentiation of cysts and tissue formations identified by palpation or X-ray mammography;

Assessment of lumps in the mammary gland of unknown etiology;

Assessment of the condition of the mammary glands with enlargement of the axillary, sub- and supraclavicular lymph nodes;

Assessment of the condition of silicone breast prostheses;

Ultrasound-guided puncture biopsy of formations.

Stomach

1. Study of the parenchymal organs of the digestive system (liver, pancreas):

Diagnosis of focal and diffuse diseases (tumors, cysts, inflammatory processes);

Diagnosis of damage during mechanical injury belly;

Detection of metastatic liver damage during malignant tumors any localization;

Diagnosis of portal hypertension.

2. Research biliary tract and gallbladder:

Diagnostics cholelithiasis with assessment of the condition of the biliary tract and identification of stones in them;

Clarification of the nature and severity of morphological changes in acute and chronic cholecystitis;

Establishing the nature of postcholecystectomy syndrome.

Ultrasound examination (Ultrasound), sonography- non-invasive examination of the human or animal body using ultrasonic waves.

Encyclopedic YouTube

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✪ Ultrasound examination

✪ Ultrasound examination of the prostate gland (echosemiotics of structural changes).

✪ Procedure: ultrasound examination of the gallbladder, part 1 - introduction

✪ ultrasound examination abdominal cavity- examination of the aorta specific example

✪ Ultrasound anatomy and liver examination techniques

Subtitles

Physical Basics

Having reached the boundary of two media with different acoustic resistance, the beam of ultrasonic waves undergoes significant changes: one part of it continues to propagate in the new medium, being absorbed to one degree or another by it, the other is reflected. The reflection coefficient depends on the difference in the acoustic resistance of tissues adjacent to each other: the greater this difference, the greater the reflection and, naturally, the greater the intensity of the recorded signal, which means the lighter and brighter it will appear on the device screen. A complete reflector is the boundary between tissue and air.

In its simplest implementation, the method allows you to estimate the distance to the separation boundary of the densities of two bodies, based on the travel time of the wave reflected from the separation boundary. More complex research methods (for example, based on the Doppler effect) make it possible to determine the speed of movement of the density interface, as well as the difference in the densities forming the boundary.

When propagating, ultrasonic vibrations obey the laws of geometric optics. In a homogeneous medium they propagate rectilinearly and at a constant speed. On the border different environments With unequal acoustic density, some of the rays are reflected, and some are refracted, continuing their linear propagation. The higher the gradient of the difference in the acoustic density of the boundary media, the larger part of the ultrasonic vibrations is reflected. Since 99.99% of vibrations are reflected at the boundary of the transition of ultrasound from air to skin, then when ultrasound scanning The patient needs to lubricate the skin surface with aqueous jelly, which acts as a transition medium. Reflection depends on the angle of incidence of the beam (greatest when the direction is perpendicular) and the frequency of ultrasonic vibrations (at higher frequencies, more is reflected).

To study the abdominal organs and retroperitoneal space, as well as the pelvic cavity, a frequency of 2.5 - 3.5 MHz is used, and a frequency of 7.5 MHz is used to study the thyroid gland.

Of particular interest in diagnostics is the use of the Doppler effect. The essence of the effect is a change in the frequency of sound due to the relative movement of the sound source and receiver. When sound bounces off a moving object, the frequency of the reflected signal changes (a frequency shift occurs).

When the primary and reflected signals overlap, beats occur, which can be heard using headphones or a loudspeaker.

Components of an ultrasound diagnostic system

Ultrasonic Wave Generator

The generator of ultrasonic waves is a sensor, which simultaneously plays the role of a receiver of reflected echo signals. The generator operates in pulse mode, sending about 1000 pulses per second. In the intervals between the generation of ultrasonic waves, the piezo sensor records the reflected signals.

Ultrasonic sensor

A complex sensor consisting of several hundred small piezocrystalline transducers operating in the same mode is used as a detector or transducer. A focusing lens is built into the sensor, which makes it possible to create focus at a certain depth.

Types of sensors

All ultrasonic sensors divided into mechanical and electronic. In mechanical scanning, scanning is carried out due to the movement of the emitter (it either rotates or swings). In electronic scanning, scanning is done electronically. The disadvantages of mechanical sensors are noise and vibration produced when the emitter moves, as well as low resolution. Mechanical sensors are obsolete and are not used in modern scanners. Three types of ultrasonic scanning are used: linear (parallel), convex and sector. Accordingly, the sensors or transducers of ultrasonic devices are called linear, convex and sector. The choice of sensor for each study is carried out taking into account the depth and nature of the position of the organ.

Linear sensors

In clinical practice, the technique is used in two directions.

Dynamic echo contrast angiography

The visualization of blood flow is significantly improved, especially in small, deeply located vessels with low blood flow velocity; the sensitivity of the color circulation and edema significantly increases; provides the ability to observe all phases of vascular contrast in real time; the accuracy of assessing stenotic lesions of blood vessels increases.

Tissue echo contrast

It is ensured by the selectivity of the inclusion of echo contrast agents in the structure of certain organs. The degree, speed and accumulation of echo contrast in unchanged and pathological tissues are different. It becomes possible to assess organ perfusion, improves contrast resolution between normal and diseased tissue, which helps to increase the accuracy of diagnosis of various diseases, especially malignant tumors.

Application in medicine

Echoencephalography

Echoencephalography, like Dopplerography, is found in two technical solutions: A-mode (in the strict sense is not considered an ultrasound examination, but is performed as part of functional diagnostics) and B-mode, which received unofficial name"neurosonography". Since ultrasound cannot effectively penetrate bone tissue, including the bones of the skull, neurosonography is performed mainly in infants through the large fontanelle) and is not used for diagnosing the brain in adults. However, materials have already been developed that will help ultrasound penetrate the bones of the body.

The use of ultrasound for diagnosis in serious damage head allows the surgeon to determine the location of hemorrhages. Using a handheld probe, the position of the midline of the brain can be established in approximately one minute. The operating principle of such a probe is based on recording an ultrasonic echo from the interface between the hemispheres.

Ophthalmology

Just like echoencephalography, it exists in two technical solutions (different devices): A-mode (usually not considered ultrasound) and B-mode.

Ultrasound probes are used to measure the size of the eye and determine the position of the lens.

Internal diseases

Ultrasound plays important role in diagnosing diseases internal organs, such as:

abdominal cavity and retroperitoneal space
- gallbladder and biliary tract
pelvic organs

Due to its relatively low cost and high availability, ultrasound is a widely used method for examining a patient and makes it possible to diagnose quite large number diseases such as oncological diseases, chronic diffuse changes in organs (diffuse changes in the liver and pancreas, kidneys and renal parenchyma, prostate gland, the presence of stones in gallbladder, kidneys, the presence of anomalies of internal organs, fluid formations in organs.

Due to physical characteristics, not all organs can be reliably examined using ultrasound, for example, hollow organs gastrointestinal tract difficult to access due to their gas content. Nevertheless, ultrasound diagnostics can be used to identify signs intestinal obstruction And indirect signs adhesive process. Using an ultrasound examination, you can detect the presence of free fluid in the abdominal cavity, if there is a lot of it, which can play a role decisive role V therapeutic tactics a number of therapeutic and surgical diseases and injuries.

Liver

Ultrasound examination of the liver is quite highly informative. The doctor evaluates the size of the liver, its structure and homogeneity, the presence of focal changes, as well as the state of blood flow. Ultrasound allows with sufficient high sensitivity and specificity to identify diffuse changes in the liver (fatty hepatosis, chronic hepatitis and cirrhosis), and focal (liquid and tumor formations). It should definitely be added that any ultrasound findings of both the liver and other organs must be evaluated only together with clinical, anamnestic data, as well as data additional examinations.

Gallbladder and bile ducts

In addition to the liver itself, the condition of the gallbladder and bile ducts is assessed - their size, wall thickness, patency, the presence of stones, and the condition of surrounding tissues are examined. Ultrasound allows in most cases to determine the presence of stones in the cavity of the gallbladder.

Pancreas

Diagnostic ultrasound examination of the fetus is also generally considered as safe method for use during pregnancy. This diagnostic procedure should only be used if there are compelling medical indications, with the least possible possible period exposure to ultrasound, which will allow obtaining the necessary diagnostic information, that is, according to the principle of the minimum acceptable or ALARA principle.

Report 875 World Organization Health Report 1998 supports the view that ultrasound is harmless. Despite the lack of data on the harm of ultrasound to the fetus, the US Food and Drug Administration considers the advertising, sale or rental of ultrasound equipment to create “fetal souvenir videos” as inappropriate, unauthorized use of medical equipment.

Ultrasound diagnostic device

Ultrasound diagnostic apparatus (ultrasound scanner) is a device designed to obtain information about the location, shape, size, structure, blood supply of organs and tissues of humans and animals.

Based on form factor, ultrasound scanners can be divided into stationary and portable (portable); by the mid-2010s, mobile ultrasound scanners based on smartphones and tablets became widespread.

Outdated classification of ultrasound machines

Depending on functional purpose devices are divided into the following main types:

ETS - echotomoscopes (devices designed mainly for examining the fetus, abdominal and pelvic organs);
EX - echocardioscopes (devices designed to study the heart);
EES - echoenceloscopes (devices designed to study the brain);
EOS - echo-ophthalmoscopes (devices designed to examine the eye).

Depending on the time of receiving diagnostic information, devices are divided into the following groups:

C - static;
D - dynamic;
K - combined.

Device classifications

Officially, ultrasound machines can be divided according to the presence of certain scanning modes, measurement programs (packages, for example, cardio package - a program for echocardiographic measurements), high-density sensors (sensors with a large number piezoelements, channels and, accordingly, higher transverse resolution), additional options (3D, 4D, 5D, elastography and others).

The term “ultrasound examination” in the strict sense can mean a study in B-mode; in particular, in Russia this is standardized and a study in A-mode is not considered an ultrasound. Old generation devices without B-mode are considered obsolete, but are still used as part of functional diagnostics.

The commercial classification of ultrasound devices generally does not have clear criteria and is determined independently by manufacturers and their dealer networks; characteristic classes of equipment are:

Primary class (B-mode)
Middle class (CDC)
High class
Premium class
Expert class

Terms, concepts, abbreviations

Advanced 3D- expanded 3D reconstruction program.
ATO- Automatic image optimization, optimizes image quality with the click of a button.
B-Flow- visualization of blood flow directly in B-mode without the use of Doppler methods.
Coded Contrast Imaging Option- coded contrast image mode, used in studies with contrast agents.
CodeScan- technology for amplifying weak echo signals and suppressing unwanted frequencies (noise, artifacts) by creating a coded sequence of pulses on transmission with the ability to decode them on reception using a programmable digital decoder. This technology allows for unsurpassed image quality and improved diagnostic quality through new scanning modes.
Color doppler (CFM or CFA)- Color Doppler - highlighting on the echogram with color (color mapping) the nature of blood flow in the area of interest. The blood flow to the sensor is usually mapped in red, and from the sensor - in blue. Turbulent blood flow is mapped in blue-green-yellow color. Color Doppler is used to study blood flow in vessels and in echocardiography. Other names for the technology are color Doppler mapping (CDC), color flow mapping (CFM) and color flow angiography (CFA). Typically, using color Doppler, changing the position of the sensor, the area of interest (vessel) is found, then pulsed Doppler is used for quantitative assessment. Color and power Doppler help in differentiating cysts from tumors since the internal contents of a cyst are avascular and therefore can never have color loci.
DICOM- the ability to transfer “raw” data over the network for storage on servers and workstations, printing and further analysis.
Easy 3D- surface three-dimensional reconstruction mode with the ability to set the transparency level.
M-mode- one-dimensional ultrasound scanning mode (historically the first ultrasound mode), in which anatomical structures are examined along the time axis, currently used in echocardiography. M-mode is used to assess the size and contractile function of the heart and the functioning of the valve apparatus. Using this mode, you can calculate the contractility of the left and right ventricles and evaluate the kinetics of their walls.
MPEGvue- quick access to stored digital data and a simplified procedure for transferring images and video clips to CD in a standard format for subsequent viewing and analysis on a computer.
Power doppler- power Doppler - qualitative assessment of low-speed blood flow, used in network studies small vessels (thyroid gland, kidneys, ovary), veins (liver, testicles), etc. More sensitive to the presence of blood flow than color Doppler. The echogram is usually displayed in an orange palette; brighter shades indicate a higher blood flow rate. Main disadvantage- lack of information about the direction of blood flow. The use of power Doppler in three-dimensional mode makes it possible to judge the spatial structure of blood flow in the scanning area. Power Doppler is rarely used in echocardiography, but is sometimes used in combination with contrast agents to study myocardial perfusion. Color and power Doppler help in differentiating cysts from tumors since the internal contents of a cyst are avascular and therefore can never have color loci.
Smart Stress- expanded capabilities of stress echo studies. Quantitative Analysis and the ability to save all scan settings for each stage of the study when imaging different segments of the heart.
Tissue Harmonic Imaging (THI)- technology for isolating the harmonic component of vibrations of internal organs caused by the passage of a basic ultrasonic pulse through the body. The useful signal is the one obtained by subtracting the base component from the reflected signal. The use of the 2nd harmonic is advisable when ultrasound scanning through tissues that intensively absorb the 1st (basic) harmonic. The technology involves the use of broadband sensors and a receiving path hypersensitivity, image quality, linear and contrast resolution improves in overweight patients. * Tissue Synchronization Imaging (TSI)- a specialized tool for the diagnosis and assessment of cardiac dysfunctions.
Tissue Velocity Imaging, Tissue Doppler Imaging (TDI)- tissue Doppler - mapping tissue movement, used in TSD and TCDC modes (tissue spectral and color Dopplerography) in echocardiography to assess myocardial contractility. By studying the directions of movement of the walls of the left and right ventricles in systole and diastole with tissue Doppler, it is possible to detect hidden zones of impaired local contractility.
TruAccess- an approach to image acquisition based on the ability to access “raw” ultrasound data.
TruSpeed- a unique set of software and hardware components for processing ultrasound data, providing ideal image quality and highest speed data processing in all scanning modes.
Virtual Convex- expanded convex image when using linear and sector sensors.
VScan- visualization and quantification of myocardial movement.
Pulsed Doppler (PW, HFPW)- pulsed Doppler (Pulsed Wave or PW) is used to quantify blood flow in vessels. The vertical time base displays the flow velocity at the point under study. Flows that move toward the sensor are displayed above the baseline, and return flow (away from the sensor) is shown below. Maximum speed flow depends on the scanning depth, pulse frequency and has a limitation (about 2.5 m/s when diagnosing the heart). High-frequency pulsed Doppler (HFPW - high frequency pulsed wave) allows you to record higher flow velocities, but also has a limitation associated with distortion of the Doppler spectrum.
Continuous wave doppler- Continuous Wave Doppler (CW) is used to quantify blood flow in vessels with high-speed flows. The disadvantage of the method is that flows are recorded throughout the entire scanning depth. In echocardiography, using continuous wave Doppler, it is possible to calculate the pressure in the cavities of the heart and great vessels in one or another phase cardiac cycle, calculate the degree of significance of the stenosis, etc. The basic equation of CW is the Bernoulli equation, which allows one to calculate the pressure difference or pressure gradient. Using the equation, you can measure the pressure difference between the chambers under normal conditions and in the presence of pathological, high-speed blood flow.

Preparing for an ultrasound

Preparing the patient for ultrasound examination (ultrasound) has great value, since it may affect the quality of the resulting image and, ultimately, the results of the examination. Ultrasound is a method based on decoding ultrasound signals returned from the organ being scanned. It is used for research various organs or body systems - abdominal cavity, pelvic organs,vessels, etc. The ultrasound method does not pose any danger or discomfort for the patient; it is very simple and accessible, and does not take much time. Ultrasound allows you to see tumors, inflammatory processes, blood clots in blood vessels and other deviations from the norm.

Ultrasound of the abdominal organs

2-3 days before the examination, it is recommended to switch to a slag-free diet and exclude from the diet foods that increase gas formation in the intestines ( raw vegetables, rich in plant fiber, whole milk, brown bread, legumes, carbonated drinks, as well as high-calorie confectionery- pastries, cakes).

It is advisable, during this period of time, to take enzyme preparations and enterosorbents (for example, Festal, Mezim-Forte, activated carbon or espumizan 1 tablet 3 times a day), which will help reduce the manifestations of flatulence.

Ultrasound of the abdominal organs must be performed on an empty stomach; if the study cannot be performed in the morning, a light breakfast is allowed.
It is not recommended to smoke before the study. If you accept medicines, warn the doctor performing the ultrasound about this.Can't conduct research after fluoroscopy of the stomach, irrigoscopy, FGDS for 3 days.

Ultrasound of the pelvic organs (bladder, uterus, appendages in women)

In girls and women who have never been sexually active, a transabdominal ultrasound examination of the pelvic organs is performed, which is carried out with complete bladder. Therefore, it is necessary not to urinate for 3-4 hours before the examination or drink 1 liter of non-carbonated liquid 1 hour before the procedure.

Women who are sexually active are examined transvaginally.No special preparation is required for transvaginal ultrasound (TVUS). If the patient has problems with the gastrointestinal tract, it is necessary to perform a cleansing enema the night before. Before the examination, you need to empty your bladder.

Ultrasound of the bladder

Transabdominal examination in men and women is performed with a full bladder. To do this, approximately 1.5 - 2 hours before the ultrasound, you need to drink 1.0-1.5 liters of still water and not urinate after that. Or: do not empty your bladder for 5 to 6 hours before the procedure.

If the ultrasound will be performed transrectally, it is necessary to do a cleansing enema on the eve of the procedure and several hours before it.

This is necessary so that there is no intestinal bloating at the time of the study. Therefore, 3 days before the procedure you need to be well prepared. Adhere to dietary restrictions to reduce gas formation: do not eat fruits and vegetables in fresh; beans, peas, lentils and other legumes; baked goods containing yeast; fresh milk and fermented milk products; alcoholic and sweet drinks.

ECHO-CG (ultrasound of the heart)

The only caveat concerns people with tachyarrhythmias and increased blood pressure: A cardiologist should be consulted immediately before the study. The doctor should say whether there is a need to reduce the pulse and/or blood pressure if the pulse is more than 90 per minute and the blood pressure is above 170/99 mmHg. This is necessary to correctly interpret the research results.

Ultrasound of the mammary glands

It is advisable to conduct breast examination on days 5-10 menstrual cycle. Before the procedure it is necessary to carry out hygiene procedures, aimed at cleansing the skin of the chest and armpit area.

Ultrasound of the prostate gland

Transabdominal ultrasound examination of the prostate gland is performed with a full bladder, so it is necessary not to urinate for 3-4 hours before the examination or drink 1 liter of still liquid 1 hour before the procedure.

Before transrectal examination of the prostate (TRUS), it is necessary to do a cleansing enema andempty your bladder.

Ultrasound of lymph nodes, soft tissues (skin, subcutaneous tissue)

No special preparation is required.

Ultrasound of the thyroid gland

No special preparation is required for the study.

For women, thyroid ultrasound is best performed 7-9 days after the end of menstruation.

It is worth remembering that during the examination the doctor may put a little pressure on the throat, which sometimes provokes gag reflex. Young people who do not suffer from digestive problems can usually withstand the procedure without developing a gag reflex. However, elderly patients are recommended to undergo the procedure in the morning and on an empty stomach. to avoid discomfort.

Kidney ultrasound

The kidneys are rarely examined in isolation from other urinary organs. For a complete diagnosis, the functioning of the adrenal glands, bladder, blood flow in the renal vessels (Doppler) is additionally assessed; according to indications, an ultrasound of the kidneys is combined with an examination of the organs of the digestive and reproductive systems.

To ensure normal visualization of the kidneys, it is necessary to take care of the cleanliness of the intestines. It should not be full at the time of the procedure. With normal digestion, a normal bowel movement in the evening or morning before the ultrasound is sufficient. It is more convenient to undergo a study scheduled for the morning on an empty stomach. The last meal in the evening should be light, 8 - 12 hours before the time of the procedure. This rule is mandatory for patients whose kidney examination is combined with an examination of the abdominal organs. During an ultrasound in the afternoon, you are allowed to have breakfast early in the morning. You can eat a white cracker, a piece of boiled meat, or porridge with water. 1 - 1.5 hours after breakfast, take activated carbon (at the rate of 1 crushed tablet for every 10 kg of body weight) or any other sorbent. Problems with stool must be eliminated. An enema cannot be done immediately before an ultrasound. If there is such a need, cleansing with an enema can be done 1 - 2 days before the test. It's better to take a mild laxative, put glycerin suppository or use a microenema (Microlax). To improve digestion, you can take enzymes (Mezim, Pancreatin, Creon) with food for 3 days before the test. Food will be better digested, release less gases and be easier to evacuate from the intestines. For flatulence, taking drugs based on simethicone (Espumizan, Simethicone, Simikol, Meteospasmin) is indicated. Excess gases from the intestines are well removed by enterosorbents (activated carbon, Enterosgel, Smecta).

Ultrasound of head and neck vessels

There is no special preparation for the ultrasound examination procedure.

However, it is worth remembering those substances that affect the condition of blood vessels, namely their tone, and on the day of the study, if possible, limit yourself in consuming these substances. These substances include: nicotine, tea, coffee, etc.

Before considering the types and directions of ultrasound examination, it is necessary to understand and understand what the diagnostic effect of ultrasound is based on. The history of ultrasound goes back to 1881, when the Curie brothers discovered the “piezoelectric effect.” Ultrasound refers to sound vibrations that lie above the threshold of perception of the human hearing organ. The “piezoelectric effect,” which produces ultrasonic vibrations, found its first application during the First World War, when sonar was first developed and used to navigate ships, determine the distance to a target, and search for submarines. In 1929, ultrasound found its application in metallurgy to determine the quality of the resulting product (flaw detection). The first attempts to use ultrasound for medical diagnostic purposes led to the advent of one-dimensional echoencephalography in 1937. Only in the early fifties of the nineteenth century was it possible to obtain the first ultrasound image of human internal organs. Since then, ultrasound diagnostics has become widely used in radiology diagnostics many pathologies and damage to internal organs. Subsequently, ultrasound diagnostics was constantly improved and expanded the scope of its application.

Types of ultrasound examination

Ultrasound examination has made a certain breakthrough in medicine, making it possible to quickly and safely, and most importantly, correctly diagnose and treat many pathologies. Currently ultrasound examination used in almost all areas of medicine. For example, using ultrasound of the abdominal cavity to determine the condition of internal organs, ultrasound and Doppler of blood vessels are used to diagnose many vascular diseases. Distinguish the following types and directions of ultrasound examination: A) Ultrasound examination with computer processing and color Doppler mapping (ultrasound of the thyroid gland, ultrasound of the liver, ultrasound of the mammary glands, ultrasound of the gallbladder, ultrasound of the pancreas, ultrasound of the bladder, ultrasound of the spleen, ultrasound of the kidneys, studies with vaginal and rectal sensors, ultrasound of the pelvic organs in women, ultrasound of the prostate in men); B) Ultrasound examination with Dopplerography, color duplex scanning(Ultrasound of brain and neck vessels, lower limbs, joints and spine, ultrasound during pregnancy).

Ultrasound examination creates images of internal organs using sound waves high frequency. Ultrasound examination is painless. Ultrasound examination is safe for pregnant women and children, as it does not involve radiation. To obtain ultrasound images, a gel is applied to the patient’s skin in the place where the examination will be carried out, then the specialist moves the ultrasound sensor of the device over this area. The computer processes the received signal and displays it on the monitor screen in the form of a three-dimensional image.

Ultrasound of the thyroid gland

In examining the thyroid gland, ultrasound examination is the leading one and allows you to determine the presence of nodes, cysts, changes in the size and structure of the gland. As practice shows, due to the physical characteristics of the structure, not all organs can be reliably examined using the ultrasound method. For example, the hollow organs of the gastrointestinal tract are difficult to access due to the predominant gas content in them. However, ultrasound examination can be used to determine signs of intestinal obstruction and indirect signs of adhesions. Using an ultrasound of the thyroid gland, it is possible to detect the presence of free fluid in the abdominal cavity, if there is a lot of it, which can play a decisive role in the treatment tactics of a number of therapeutic and surgical diseases and injuries.

Ultrasound of the liver

Ultrasound examination of the liver is quite high informative method diagnostics The use of this type of examination allows the specialist to assess the size, structure and homogeneity, as well as the presence of focal changes and the state of blood flow. Ultrasound of the liver allows one to detect, with fairly high sensitivity and specificity, both diffuse changes in the liver (fatty hepatosis, chronic hepatitis and cirrhosis) and focal ones (fluid and tumor formations). The patient needs to know that any ultrasound findings of both the liver and other organs must be evaluated and considered only in conjunction with clinical, anamnestic data, as well as data from additional examinations. Only in this case will a specialist be able to reproduce the complete picture and make a correct and adequate diagnosis.

Ultrasound of the mammary glands (ultrasound mammography)

The main use of ultrasound examination in mammology is to clarify the nature of formations in the mammary gland. Ultrasound mammography is the most complete and effective examination of the mammary glands. Modern ultrasound examination of the mammary gland allows, with maximum detail, to equally effectively assess the condition of both superficial and deep tissues of the mammary gland of any size and structure. Due to the maximum detail of tissues, it is possible to bring even closer ultrasound anatomy mammary glands to their morphological structure.

Ultrasound of the mammary glands is like independent method identifying benign and malignant tumors in the mammary gland, and additionally, used in conjunction with mammography. In some cases, ultrasound examination is superior to mammography in its effectiveness. For example, when examining dense mammary glands in young women; in women who have fibrocystic mastopathy; when cysts are detected. In addition, ultrasound of the mammary glands is used for dynamic monitoring of already identified benign breast formations, which makes it possible to identify dynamics and take adequate measures in a timely manner. Modern development medical technologies led to the fact that the ultrasound examination protocol included not only an assessment of the condition of the mammary glands, but also regional lymph nodes (axillary, supraclavicular, subclavian, retrosternal, prothoracic). One of components Ultrasound examination is an assessment of the blood flow of the mammary glands using special technique– Dopplerography (spectral and color-coded – color Doppler mapping (CDC) and power Dopplerography), which is crucial in identifying malignant formations of the mammary gland at the most early stages development.

Ultrasound of the gallbladder

Ultrasound of the gallbladder is an informative diagnostic method. To identify various pathologies gall bladder specialists often use ultrasound examination. The gallbladder is responsible for storing and releasing bile produced by the liver. This process can be disrupted by many diseases to which the organ is susceptible: stones, polyps, cholecystitis and even cancer. The most common is dyskinesia of the gallbladder and biliary tract.

The purpose of an ultrasound examination is to determine the size, position, and examination of the walls of the gallbladder and the contents of the cavity. Echography of the gallbladder and bile ducts must be performed on an empty stomach, no earlier than 8–12 hours after a meal. This is necessary to sufficiently fill the bladder with bile. The patient is examined in three positions - on the back, on the left side, standing, at the height of a deep inspiration. Ultrasound of the gallbladder is completely safe and does not cause complications. Indications for an ultrasound scan of the gallbladder include clinical suspicion of gallbladder disease, including acute, as well as palpable formation in the projection of the gallbladder, cardialgia of unknown nature, dynamic observation during conservative treatment chronic cholecystitis, cholelithiasis, suspected gallbladder tumor.

Ultrasound of the pancreas

Ultrasound examination of the pancreas allows the doctor to obtain additional information for diagnosis and prescription proper treatment. An ultrasound examination of the pancreas evaluates its size, shape, contours, homogeneity of the parenchyma, and the presence of formations. Unfortunately, high-quality ultrasound of the pancreas is often quite difficult, since it can be partially or completely blocked by gases in the stomach, small and large intestines. The most common conclusion made by ultrasound doctors, “diffuse changes in the pancreas,” may reflect how age-related changes(sclerotic, fatty infiltration), and possible changes due to chronic inflammatory processes. In any case, ultrasound examination of the pancreas is an integral stage of adequate treatment.

Ultrasound of the kidneys, adrenal glands and retroperitoneum

Carrying out an ultrasound examination of the retroperitoneum, kidneys and adrenal glands is a rather difficult procedure for an ultrasound specialist. This is primarily due to the peculiarities of the location of these organs, the complexity of their structure and versatility, as well as the ambiguity in the interpretation of the ultrasound picture of these organs. When examining the kidneys, their size, location, shape, contours and structure of the parenchyma and pyelocaliceal system are assessed. Ultrasound examination can detect kidney abnormalities, the presence of stones, fluid and tumor formations, as well as changes due to chronic and acute pathological processes of the kidneys.

IN recent years Methods of ultrasound diagnostics and treatment by puncture under ultrasound control have become widely developed. This section of ultrasound diagnostics has a great future, since it allows making an accurate morphological diagnosis. An additional advantage Carrying out therapeutic punctures under ultrasound control is significantly less traumatic compared to conventional medical procedures. For example, the pathological area from which the material for research is taken is located deep in the body, therefore, without monitoring the progress of the biopsy using special imaging equipment, one cannot be sure that the material for research was taken from the right place. To control progress needle biopsy Ultrasound is used. This method is highly informative and allows you to easily determine the position of the needle in the organ and be confident in the correctness of the biopsy. Without such control, biopsy of many organs is impossible.

In conclusion, it should be noted that the types and directions of ultrasound examination are so multifaceted and also applicable in the most different areas modern medicine that it is not possible to fully cover ultrasound diagnostics in one material. Today, ultrasound examination, due to its relatively low cost and wide availability, is a common method of examining a patient. Ultrasound diagnostics allows us to identify a fairly large number of diseases, such as cancer, chronic diffuse changes in organs. For example, diffuse changes in the liver and pancreas, kidneys and renal parenchyma, prostate gland, the presence of stones in the gall bladder, kidneys, the presence of anomalies of internal organs, fluid formations in organs, etc. Monitor your health, do not forget about preventive examination and you will save yourself from many problems in the future.

Chapter 3. Basics and clinical application ultrasound diagnostic method

Chapter 3. Basics and clinical applications of ultrasound diagnostic method

An ultrasound diagnostic method is a method of obtaining a medical image based on registration and computer analysis of ultrasonic waves reflected from biological structures, i.e., based on the echo effect. The method is often called echography. Modern ultrasound machines (ultrasound) are universal high-resolution digital systems with the ability to scan in all modes (Fig. 3.1).

Rice. 3.1. Ultrasound examination of the thyroid gland

Ultrasound diagnostic power is virtually harmless. Ultrasound has no contraindications, is safe, painless, atraumatic and not burdensome. If necessary, it can be carried out without any

preparation of patients. Ultrasound equipment can be delivered to any functional department for the examination of non-transportable patients. A great advantage, especially when the clinical picture is unclear, is the possibility of simultaneous examination of many organs. The great cost-effectiveness of echography is also important: the cost of ultrasound is several times less than X-ray examinations, and even more so computed tomography and magnetic resonance imaging.

However, the ultrasonic method also has some disadvantages:

High hardware and operator dependence;

Greater subjectivity in the interpretation of echographic images;

Low information content and poor demonstrativeness of frozen images.

PHYSICAL AND BIOPHYSICAL BASICS OF ULTRASONIC DIAGNOSTIC METHOD

Ultrasound refers to sound vibrations that lie above the threshold of perception by the human hearing organ, i.e., having a frequency of more than 20 kHz. The physical basis of ultrasound is the piezoelectric effect discovered in 1881 by the Curie brothers. Its practical application is associated with the development of ultrasonic industrial flaw detection by the Russian scientist S. Ya. Sokolov (late 20s - early 30s of the twentieth century). The first attempts to use the ultrasound method for diagnostic purposes in medicine date back to the late 30s. XX century. The widespread use of ultrasound in clinical practice began in the 1960s.

The essence of the piezoelectric effect is that when single crystals of certain chemical compounds (quartz, titanium, barium, cadmium sulfide, etc.) are deformed, in particular under the influence of ultrasonic waves, electric charges of opposite sign appear on the surfaces of these crystals. This is the so-called direct piezoelectric effect (piezo in Greek means to press). On the contrary, when applying alternating voltage to these single crystals electric charge mechanical vibrations occur in them with the emission of ultrasonic waves. Thus, the same piezoelectric element can alternately be a receiver and a source of ultrasonic waves. This part in ultrasound machines is called an acoustic transducer, transducer or sensor.

one complete oscillation; frequency - the number of oscillations per unit time; length - the distance between points of one phase and the speed of propagation, which depends mainly on the elasticity and density of the medium. The length of a wave is inversely proportional to its frequency. The shorter the wavelength, the higher the resolution of the ultrasonic device. Medical ultrasound diagnostic systems typically use frequencies from 2 to 10 MHz. The resolution of modern ultrasonic devices reaches 1-3 mm.

Any environment, including various tissues of the body, prevents the propagation of ultrasound, i.e., it has different acoustic resistance, the value of which depends on their density and the speed of ultrasound. The higher these parameters, the greater the acoustic resistance. This general characteristic of any elastic medium is designated by the term “impedance”.

ULTRASONIC RESEARCH METHODS

Currently, ultrasound in B- and M-mode and Doppler sonography are used in clinical practice.

B-mode is a technique that provides information in the form of two-dimensional gray scale tomographic images of anatomical structures in real time, which makes it possible to assess their morphological state. This mode is the main one; in all cases, ultrasound begins with its use.

Modern ultrasound equipment detects minute differences in the levels of reflected echoes, which are displayed in many shades of gray. This makes it possible to distinguish between anatomical structures that even slightly differ from each other in acoustic resistance. The lower the echo intensity, the darker the image, and, conversely, the greater the energy of the reflected signal, the brighter the image.

Dense biological tissues are echogenic (light gray). If ultrasonic waves are completely reflected, then objects appear hyperechoic (bright white), and behind them there is a so-called acoustic shadow, which looks like a dark path (see Fig. 3.3).

abcd Rice. 3.2. Scale of levels of echogenicity of biological structures: a - anechoic; b - hypoechoic; c - medium echogenicity (echopositive); d - increased echogenicity; d - hyperechoic

Rice. 3.3. Echograms of the kidneys in a longitudinal section with the designation of various structures

M-mode - one-dimensional. In it, one of the two spatial coordinates is replaced by a time one, so that the distance from the sensor to the located structure is plotted along the vertical axis, and time is plotted along the horizontal axis. This mode is mainly used for cardiac examination. It provides information in the form of curves reflecting the amplitude and speed of movement of cardiac structures (see Fig. 3.4).

Dopplerography is a technique based on the use of the physical Doppler effect (named after the Austrian physicist). The essence of this effect is that ultrasonic waves are reflected from moving objects with a changed frequency. This frequency shift is proportional

the speed of movement of the located structures, and if their movement is directed towards the sensor, the frequency of the reflected signal increases, and, conversely, the frequency of waves reflected from the receding object decreases. We encounter this effect all the time, observing, for example, changes in the frequency of sound from cars, trains, and planes rushing past.

Streaming spectral Dopplerography designed to assess blood flow in relatively large

Rice. 3.4.M - modal curve of movement of the anterior mitral valve leaflet

There are two options for flow Dopplerography: continuous (constant wave) and pulsed.

divided place is a disadvantage of continuous Dopplerography. At the same time, it also has an important advantage: it allows the measurement of high blood flow rates.

Pulsed Dopplerography is based on the periodic emission of a series of pulses of ultrasonic waves, which, reflected from red blood cells, sequentially perceive

Rice. 3.5.Doppler spectrogram of transmitral blood flow

with the same sensor. In this mode, signals reflected only from a certain distance from the sensor are recorded, which is set at the discretion of the doctor. The place where blood flow is studied is called the reference volume (CV). The ability to assess blood flow at any given point is the main advantage of pulsed Doppler ultrasound.

Color Doppler mapping based on color coding of the Doppler shift value of the emitted frequency. The technique provides direct visualization of blood flows in the heart and in relatively large vessels (see Fig. 3.6 on the color insert). Red color corresponds to the flow going towards the sensor, blue - from the sensor. Dark shades of these colors correspond to low speeds, light shades- high. This technique allows you to assess both the morphological state of blood vessels and the state of blood flow. A limitation of the technique is the inability to obtain images of small blood vessels with low blood flow speed.

The capabilities of color Doppler mapping and power Doppler are combined in the technique convergent color Dopplerography.

The combination of B-mode with flow or energy color mapping is designated as a duplex study, which provides the greatest amount of information.

3D Doppler and 3D Power Doppler- these are techniques that make it possible to observe a three-dimensional picture of the spatial arrangement of blood vessels in real time from any angle, which makes it possible to accurately assess their relationship with various anatomical structures and pathological processes, including malignant tumors.

Echo contrast. This technique is based on the intravenous administration of special contrast agents containing free microbubbles.

gas To achieve clinically effective contrast enhancement, the following prerequisites are required. When such echocontrast agents are administered intravenously, only those substances that freely pass through the capillaries of the pulmonary circulation can enter the arterial bed, i.e., gas bubbles should be less than 5 microns. The second mandatory condition is the stability of gas microbubbles when they circulate in the general vascular system for at least 5 minutes.

The diagnostic capabilities of the ultrasound method have also expanded due to the emergence of new technologies for obtaining and post-processing of echographic images. These include, in particular, multi-frequency sensors, technologies for forming wide-format, panoramic, and three-dimensional images. Promising directions for further development of the ultrasound diagnostic method are the use of matrix technology for collecting and analyzing information about the structure of biological structures; creation of ultrasound devices that provide images of full sections of anatomical areas; spectral and phase analysis of reflected ultrasonic waves.

CLINICAL APPLICATION OF ULTRASONIC DIAGNOSTIC METHOD

Ultrasound is currently used in many areas:

Planned studies;

Emergency diagnostics;

Monitoring;

Intraoperative diagnostics;

Postoperative studies;

Monitoring the implementation of diagnostic and therapeutic instrumental manipulations (punctures, biopsies, drainage, etc.);

Screening.

Emergency ultrasound should be considered the first and mandatory method of instrumental examination of patients with acute surgical diseases abdominal and pelvic organs. At the same time, the diagnostic accuracy reaches 80%, the accuracy of recognizing damage to parenchymal organs is 92%, and the detection of fluid in the abdominal cavity (including hemoperitoneum) is 97%.

Monitoring ultrasounds are performed multiple times at different intervals during an acute pathological process to assess its dynamics, the effectiveness of therapy, and early diagnosis of complications.

The goals of intraoperative studies are to clarify the nature and extent of the pathological process, as well as to monitor the adequacy and radicality of surgical intervention.

Ultrasound in the early stages after surgery is aimed mainly at establishing the cause of the unfavorable course of the postoperative period.

Screening ultrasounds, i.e. studies without medical indications, are held for early detection diseases that have not yet manifested clinically. The feasibility of these studies is evidenced, in particular, by the fact that the frequency of newly diagnosed diseases of the abdominal organs during screening ultrasound of “healthy” people reaches 10%. Excellent results in the early diagnosis of malignant tumors are obtained by screening ultrasound of the mammary glands in women over 40 years of age and of the prostate in men over 50 years of age.

Ultrasound can be performed by both external and intracorporeal scanning.

It is possible to use high-frequency transducers, due to which the resolution of the method sharply increases, and it becomes possible to high-quality visualize the smallest structures that are inaccessible with external scanning. For example, transrectal ultrasound, compared with external scanning, provides important additional diagnostic information in 75% of cases. The detection rate of intracardiac thrombi with transesophageal echocardiography is 2 times higher than with external examination.

The general patterns of formation of an echographic gray scale image are manifested by specific patterns characteristic of a particular organ, anatomical structure, or pathological process. In this case, their shape, size and position, the nature of the contours (smooth/uneven, clear/fuzzy), internal echo structure, displacement, and for hollow organs (gallbladder and urinary bladder), in addition, the condition of the wall (thickness, echo density) must be assessed , elasticity), the presence of pathological inclusions in the cavity, primarily stones; degree of physiological contraction.

Cysts filled with serous fluid appear as round, uniformly anechoic (black) zones surrounded by an echo-positive (gray) rim of the capsule with smooth, clear contours. A specific echographic sign of cysts is the effect of dorsal enhancement: the posterior wall of the cyst and the tissues behind it look lighter than the rest of the length (Fig. 3.8).

Cavity formations with pathological contents (abscesses, tuberculosis cavities) differ from cysts in the unevenness of their contours and, most importantly,

most importantly, the heterogeneity of the echo-negative internal echo structure.

Inflammatory infiltrates are characterized by an irregular round shape, unclear contours, and evenly and moderately reduced echogenicity of the pathological process area.

The echographic picture of hematoma of parenchymal organs depends on the time that has passed since the injury. In the first few days it is homogeneously echo-negative. Then echo-positive inclusions appear in it, which are a reflection blood clots, the number of which is constantly growing. After 7-8 days, the reverse process begins - lysis of blood clots. The contents of the hematoma again become homogeneously echo-negative.

The echostructure of malignant tumors is heterogeneous, with zones of the entire spectrum

Rice. 3.8.Sonographic image of a solitary renal cyst

echogenicity: anechoic (hemorrhage), hypoechoic (necrosis), echo-positive (tumor tissue), hyperechoic (calcification).

The echographic picture of the stones is very demonstrative: a hyperechoic (bright white) structure with an acoustic echo-negative dark shadow behind it (Fig. 3.9).

Rice. 3.9. Sonographic image of gallstones

INDICATIONS FOR Ultrasound

Head

1. Examination of the brain in young children, mainly if a congenital disorder of its development is suspected.

2. Examination of cerebral vessels to determine the causes of the disorder cerebral circulation and to evaluate the effectiveness of vascular operations performed.

3. Examination of the eyes to diagnose various diseases and injuries (tumors, retinal detachment, intraocular hemorrhages, foreign bodies).

4. Examination of the salivary glands to assess their morphological state.

5. Intraoperative control of the total removal of brain tumors.

Neck

1. Study of the carotid and vertebral arteries:

Prolonged, frequently recurring severe headaches;

Frequently recurring fainting;

Clinical signs of cerebrovascular accidents;

Clinical subclavian steal syndrome (stenosis or occlusion of the brachiocephalic trunk and subclavian artery);

Mechanical trauma (vascular damage, hematoma).

2. Study of the thyroid gland:

Any suspicion of her illness;

3. Examination of lymph nodes:

Suspicion of their metastatic damage when a malignant tumor of any organ is detected;

Lymphomas of any localization.

4. Non-organ neoplasms of the neck (tumors, cysts).

Breast

1. Heart examination:

Diagnosis of congenital heart defects;

Diagnosis of acquired heart defects;

Quantitative assessment of the functional state of the heart (global and regional systolic contractility, diastolic filling);

Assessment of the morphological state and function of intracardial structures;

Identification and establishment of the degree of disturbances of intracardiac hemodynamics (pathological shunting of blood, regurgitant flows due to insufficiency of the heart valves);

Diagnosis of hypertrophic myocardiopathy;

Diagnostics of intracardiac blood clots and tumors;

Detection of ischemic myocardial disease;

Determination of fluid in the pericardial cavity;

Quantification of pulmonary arterial hypertension;

Diagnosis of heart damage due to mechanical trauma to the chest (bruises, ruptures of walls, septa, chords, valves);

Assessment of the radicality and effectiveness of heart surgery.

2. Examination of the respiratory organs and mediastinum:

Determination of fluid in the pleural cavities;

Clarification of the nature of lesions of the chest wall and pleura;

Differentiation of tissue and cystic neoplasms of the mediastinum;

Assessment of the condition of the mediastinal lymph nodes;

Diagnosis of thromboembolism of the trunk and main branches of the pulmonary artery.

3. Examination of the mammary glands:

Clarification of uncertain radiological data;

Differentiation of cysts and tissue formations identified by palpation or X-ray mammography;

Assessment of lumps in the mammary gland of unknown etiology;

Assessment of the condition of the mammary glands with enlargement of the axillary, sub- and supraclavicular lymph nodes;

Assessment of the condition of silicone breast prostheses;

Ultrasound-guided puncture biopsy of formations.

Stomach

1. Study of parenchymal organs digestive system(liver, pancreas):

Diagnosis of focal and diffuse diseases (tumors, cysts, inflammatory processes);

Diagnosis of injuries due to mechanical trauma of the abdomen;

Detection of metastatic liver damage in malignant tumors of any location;

Diagnosis of portal hypertension.

2. Study of the biliary tract and gallbladder:

Diagnosis of cholelithiasis with assessment of the condition of the biliary tract and identification of stones in them;

Clarification of character and severity morphological changes for acute and chronic cholecystitis;

Establishing the nature of postcholecystectomy syndrome.

3. Stomach examination:

Differential diagnosis of malignant and benign lesions;

Estimation of local prevalence of gastric cancer.

4. Intestinal examination:

Diagnosis of intestinal obstruction;

Assessment of local prevalence of rectal cancer;

Diagnosis of acute appendicitis.

5. Abdominal cavity examination:

Diagnosis of diffuse peritonitis;

Diagnosis of intraperitoneal non-organ abscesses;

Differentiation of intraperitoneal abscesses from inflammatory infiltrates.

6. Study of the kidneys and upper urinary tract:

Diagnosis of various diseases and assessment of the nature and severity of existing morphological changes;

Assessment of the local prevalence of malignant kidney tumors;

Changes in urine tests that persist for more than 2 months;

Determining the causes of hematuria, anuria;

Differential diagnosis renal colic and others acute diseases abdomen ( acute cholecystitis, acute appendicitis, intestinal obstruction);

Clinical signs of symptomatic arterial hypertension;

Diagnosis of damage due to mechanical trauma of the abdomen and lumbar region.

7. Examination of lymph nodes:

Detection of their metastatic lesions in malignant tumors of the abdominal and pelvic organs;

Lymphomas of any localization.

8. Examination of the abdominal aorta and inferior vena cava:

Diagnostics of abdominal aortic aneurysms;

Detection of stenoses and occlusions;

Detection of phlebothrombosis of the inferior vena cava.

Pelvis

1. Examination of the lower urinary tract (distal part of the ureters, bladder):

Determination of residual urine in the bladder with bladder outlet obstruction.

2. Examination of the internal genital organs in men (prostate, seminal vesicles):

Diagnosis of various diseases;

Assessment of the local prevalence of malignant tumors;

Determination of the stage of benign prostatic hyperplasia.

3. Examination of the internal genital organs in women:

Diagnosis of various diseases;

Determining the causes of infertility;

Determination of gestational age;

Monitoring the course of pregnancy;

Determining the sex of the fetus;

Determination of the expected body weight and length of the fetus;

Determination of the functional state (“biophysical profile”) of the fetus;

Diagnosis of ectopic pregnancy;

Diagnostics intrauterine death fetus;

Diagnosis of congenital malformations and fetal diseases.

Spine

1. Diagnosis of degenerative-dystrophic lesions.

2. Diagnosis of damage to soft tissue structures of the spine due to mechanical trauma.

3. Diagnosis of birth injuries and their consequences in newborns and children of the 1st year of life.

Limbs

1. Diagnosis of damage to muscles, tendons, and ligaments.

2. Diagnosis of diseases and injuries of extra- and intra-articular structures.

3. Diagnosis of inflammatory and tumor diseases bones and soft tissues.

4. Diagnostics congenital disorders development of the limbs (congenital dislocation of the hip, foot deformities, muscle deficiency).

Peripheral blood vessels

1. Diagnosis of arterial aneurysms.

2. Diagnosis of arteriovenous anastomosis.

3. Diagnosis of thrombosis and embolism.

4. Diagnosis of stenoses and occlusions.

5. Diagnosis of chronic venous insufficiency.

6. Diagnosis of vascular damage due to mechanical trauma.

In general, the ultrasonic method has become an integral part clinical examination patients, and its diagnostic capabilities continue to expand.

Encyclopedic YouTube

Subtitles

Physical Basics

Components of an ultrasound diagnostic system

Ultrasonic Wave Generator

Ultrasonic sensor

Types of sensors

Linear sensors

Dynamic echo contrast angiography

Tissue echo contrast

Application in medicine

Echoencephalography

Ophthalmology

Internal diseases

Liver

Gallbladder and bile ducts

Pancreas

Ultrasound diagnostic device

Outdated classification of ultrasound machines

Device classifications

Terms, concepts, abbreviations

Types of ultrasound examination

Ultrasound of the thyroid gland

Ultrasound of the liver

Ultrasound of the mammary glands (ultrasound mammography)

Ultrasound of the gallbladder

Ultrasound of the pancreas

Ultrasound of the kidneys, adrenal glands and retroperitoneum

Chapter 3. Basics and clinical applications of ultrasound diagnostic method

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