Modern ultrasound methods in obstetrics. Ultrasound diagnostics in gynecology. Radiation safety of ultrasound examination

In modern medicine, there is one hardware method of examination, without which not a single independent branch of this general science can do today - this is the ultrasound method. In short, it is called ultrasound. Today this is the most common and safe method of cavity, organ and tissue research. It is carried out by exposing the organ or tissue being examined to ultrasonic waves.

Scientists drew attention to the fact that ultrasonic waves have the ability to freely penetrate tissue, and special equipment records on monitors a clear image of everything that is in the zone of action of the waves. It is this feature that allows specialists to identify various deviations of tissues and organs of the body from the norm. And the fact that this method of research poses absolutely no additional threat to the health of the subject has made the ultrasound method the most popular and in demand today.

Another advantage and The peculiarity of ultrasound is its painlessness and the quality of information received about the status of the survey. Ultrasound examinations occupy a special place in obstetrics. This method makes it possible to accurately identify many gynecological and obstetric problems at the earliest stages. Among them are:

In addition, using ultrasound waves, pregnancy and its timing, as well as ectopic pregnancy can be easily determined. In obstetrics, there is one immutable rule for conducting this type of examination - the bladder must be full at the time of the examination.

Advantages of ultrasound in obstetrics

This method makes it possible to examine in detail all the female organs hidden inside the small pelvis, without causing any inconvenience to the patient. On the monitor screen you can easily examine the uterine cavity, determine the natural size and volume of the ovaries, and their anatomical position. An ultrasound examination of the cavities inside the small pelvis quite easily detects tumors of oncological and non-oncological etiology; one can find out the condition of the bladder and genital organs after surgical interventions. Such studies should be carried out within 5–6 days from the start of periodic discharge. During this period, the lining of the uterus (endometrium) becomes thinner, and this makes it possible to more accurately determine the presence of polyps, fibroids, and fibroids.

Speaking of features conducting ultrasound examinations in obstetrics , first of all, I would like to say that there are two types of ultrasound examinations:

These are completely different research methods, so we will consider each of them in detail and separately.

Methods for performing obstetric ultrasound

There are such methods performing an obstetric ultrasound :

• 1. Transabdominal examination. It is performed while lying on a couch. This study is intended mainly to identify pathologies of intrauterine development of the fetus and determine the general course of pregnancy. In this case, the examination is carried out through the abdominal wall. To do this, a special gel is applied to the woman’s stomach. During the study, a special transmitter is used, the signals from which are sent to a computer for processing and then displayed on the monitor screen. Thus, the doctor has the opportunity to form an accurate opinion about the condition of the fetus or about pathologies that prevent pregnancy. It is during a transabdominal examination that a woman’s bladder should be full.
• 2. Transvaginal examination. It is carried out in contrast to the first research method with an empty bladder. This is an immutable circumstance, otherwise the specialist will not be able to guarantee that the monitor screen will have a clear picture necessary to establish obvious or possible pathology of the internal organs of the small pelvis. With this method of ultrasound examination, a special sensor is inserted into the vagina. True, before insertion, a latex tip must be put on the sensor, but most often a simple condom is used.

During a transvaginal examination, the doctor makes an opinion:

Besides Ultrasound in obstetrics helps determine the sex of the unborn child with almost one hundred percent accuracy.

Reasons for performing an ultrasound during pregnancy

The main reason for conducting ultrasound examinations of pregnant women is the need to determine a more accurate picture of the course of pregnancy and its timing. What is the reason for this need?

• 1. The family may not be aware of any congenital or genetic abnormalities that can cause pathology in fetal development. Ultrasound makes it possible to detect the development of pathology in the early stages.
• 2. When there is a need to determine the exact timing of pregnancy.
• 3. With the detection of multiple pregnancy.
• 4. With determination of the anatomical location of the placenta.
• 5. With the detection of pathologies that impede the proper course of pregnancy.
• 6. With the identification of some deviations in fetal development from the norm.

The latter circumstance has many quite serious reasons. For example, an ultrasound at the fourteenth week can reveal the presence of Down syndrome in the fetus. At this time, it is possible to terminate the pregnancy. Therefore, it is so important to conduct such a study at this particular time. An ectopic pregnancy can also be detected. If you do not pay proper attention to this problem, a specific threat to a woman’s life may arise.

Detecting a multiple pregnancy allows young parents to prepare mentally and financially for such a significant event. And most importantly when performing ultrasound in obstetrics For a doctor, this is the opportunity to conduct research in real time and the ability to prescribe timely and the only correct treatment.

In recent decades, ultrasound diagnostics has been widely used by doctors of all specialties. With the advent of this research method, the dream of many generations of doctors to see with their own eyes a developing child in utero without any harmful effects on it came true. Ultrasound in obstetrics makes it possible to answer questions that constantly arise for the doctor: what is the duration of pregnancy, the location of the fetus in the uterus, its condition, the presence of malformations, the localization of the placenta, the quantity and quality of amniotic fluid.

Ultrasound in obstetrics makes it possible to detect conditions such as multiple pregnancy and hydatidiform mole, abruption and placenta previa, and non-developing pregnancy. The method makes it possible to predict the outcome of pregnancy, which is especially important in the first trimester.

Until now, obstetricians, when performing intrauterine operations (surgical and pharmacological abortions, diagnostic curettages), worked “blindly”, but now a unique opportunity has arisen to work under vision control. Today, in almost all institutions, operational interruption in the early stages and up to 12 weeks are carried out under ultrasound control, which can significantly reduce the number of complications. It is impossible to perform chorionic aspiration, much less cordocentesis, without ultrasound imaging (USV). Methods of intraoperative ultrasound diagnostics (USD) are being developed and implemented.

Ultrasound during pregnancy

Ultrasound in the first trimester can be used from the early stages of pregnancy; mass ultrasound up to 8 weeks in case of desired pregnancy is carried out for medical reasons. We have developed indications for the use of ultrasound in the first trimester:

• presence of bloody discharge;
• symptoms of threatened miscarriage, especially with recurrent miscarriage;
• discrepancy between the size of the uterus and the gestational age (early diagnosis of multiple pregnancy, non-developing pregnancy, trophoblastic disease);
• exclusion of pregnancy with uterine fibroids;
• exclusion of genetic pathology, including anaembryony (absence of a fetus in the sac);
• exclusion of ectopic pregnancy;
• before surgical or pharmacological interruption.

At the end of the 1st trimester, that is, within 10-14 weeks, an ultrasound scan is performed for all pregnant women (first screening). The purpose of the first screening is to exclude developmental defects that can be diagnosed within this time frame; identification of early signs of chromosomal pathology; deciding on the advisability of continuing the pregnancy; making a prognosis for the course of pregnancy.

In the 2nd trimester of pregnancy, which corresponds to 20-24 weeks, a second ultrasound screening is performed. It allows you to study the main parameters of a child’s intrauterine development, eliminate developmental delays and defects, evaluate the structure and anatomical parameters of the fetus, and determine the quantity and quality of amniotic fluid. The location of the placenta, its thickness, stage of maturity, its structure and density are determined.

In addition, the anatomical features of the expectant mother are assessed: the body and cervix, the condition of the appendages; the threat is confirmed or eliminated termination of pregnancy.

By assessing all ultrasound parameters, the doctor clarifies the management plan for the pregnant woman.

The third period required for ultrasound (3rd screening) is 30-34 weeks of pregnancy.

The volume of parameters studied remains the same as in the 2nd trimester. Particular attention is paid to the condition of the fetus and placenta. Developmental delays, entanglement of the fetus with the umbilical cord, hypoxic changes in internal organs, and intrauterine infection are excluded.

Ultrasound in the 3rd trimester makes it possible to prevent complications, correct identified changes, and determine the optimal time and method of delivery to obtain a healthy baby.

In addition to the mandatory three-time ultrasound, the method can be used multiple times according to indications. Long-term use of ultrasound in obstetrics (more than 30 years), as well as preliminary and subsequent experimental studies, have not revealed the harmful effects of ultrasound on a developing child in utero.

The medical clinic "NORMA" on Arbatskaya uses the original author's method (S. A. Danilov, 1977) to assess the condition of an intrauterine developing child from the middle of the 2nd trimester, that is, from 20 weeks of pregnancy. It makes it possible to identify preclinical forms of changes in the feto-placental system, the causes of fetal suffering, and the ability to correct them in a timely manner, monitor the effectiveness of treatment measures, and change the management plan taking into account the identified violations.

The use of ultrasound in obstetrics allows you to avoid intrauterine fetal death and give birth to a healthy baby on time without complications for the mother.

Sergey Arkadyevich Danilov.

Modern advances in clinical diagnostics are largely determined by the improvement of research methods. A significant leap in this issue was achieved thanks to the development and implementation of fundamentally new methods of obtaining medical images, including the ultrasound method. Extremely valuable is the ability of echography to visualize the internal structure of parenchymal organs, which was inaccessible to traditional X-ray examination. Thanks to the high information content and reliability of the ultrasound method, the diagnosis of many diseases and injuries has risen to a qualitatively new level. Currently, along with computed tomography and other more modern methods, ultrasound diagnostics is used everywhere and is one of the leading diagnostic methods in many areas of clinical medicine.

In recent years, due to the very wide spread of ultrasound equipment, its availability for any, even very small medical institutions. There is a growing need for specialists who are fluent in the methods and techniques of ultrasound examination.

Physical basis of ultrasound diagnostics

Ultrasound refers to sound vibrations that lie above the threshold of perception of the human hearing organ. The piezoelectric effect, due to which ultrasonic vibrations are produced, was discovered in 1881 by the brothers P. Curie and J.-P. Curie. It found its application during the First World War, when K.V. Shilovsky and P. Langevin developed sonar, which was used to navigate ships, determine the distance to a target, and search for submarines. In 1929 S.Ya. Sokolov used ultrasound for non-destructive testing in metallurgy (flaw detection). This prominent Soviet acoustic physicist was the founder of ultrasonic introscopy and the author of the most commonly used and completely different methods of modern sound vision.

Attempts to use ultrasound for medical diagnostic purposes led to the advent of one-dimensional echoencephalography in 1937. However, only in the early fifties it was possible to obtain ultrasound images of human internal organs and tissues. Since then, ultrasound diagnostics has become widely used in the radiological diagnosis of many diseases and injuries of internal organs.

Biophysics of ultrasound.

From the point of view of the physics of ultrasound, the tissues of the human body are similar in their properties to a liquid medium, therefore the pressure of an ultrasonic wave on them can be described as a force acting on the liquid.

The change in pressure in the medium can occur perpendicular to the plane of vibration of the ultrasound source. In this case, the fullness is called longitudinal. In ultrasound diagnostics, the main information is carried primarily by longitudinal waves. In solids, such as bones or metals, transverse waves occur.

Sound waves are mechanical in nature, since they are based on the displacement of particles of an elastic medium from the equilibrium point. It is due to elasticity that sound energy is transferred through the fabric. Elasticity is the ability of an object, after being compressed or stretched, to regain its size and shape. The speed of ultrasound propagation depends primarily on the elasticity and density of the tissue. The greater the density of the material, the slower ultrasonic waves should propagate in it (with the same elasticity). But this physical parameter should be approached with caution. The speed of sound when passing through different media of a biological organism can be different; the table shows the speed of propagation of ultrasound in various media.

Different types of ultrasound waves use different types of ultrasound waves. The most important parameters are the radiation frequency, the diameter of the transducer surface and the focusing of the ultrasonic beam. Medical ultrasound diagnostic systems typically use frequencies of 1; 1.6; 2.25; 3.5; 5 and 10 MHz.

The devices have the ability to regulate the emitted and received signals, and it is also possible to enhance the image of echo signals.

Radiation safety of ultrasound examination

Ultrasound is widely used in medicine, although unlike the technical field where low-frequency ultrasound is used, for which there are radiation standards, in medicine everything is much more complicated. On the one hand, there is no possibility to carry out direct dosimetry of radiation in the working beam, especially at depth; on the other hand, it is very difficult to take into account the scattering, absorption and attenuation of ultrasound by biological tissues. In addition, when working with real-time devices, it is almost impossible to take into account the exposure, since the duration of the sound, as well as its direction and depth, vary widely.

The propagation of ultrasound in biological media is accompanied by mechanical, thermal, and physicochemical effects. As a result of the absorption of ultrasound by tissues, acoustic energy is converted into thermal energy. Another type of mechanical action is cavitation, which leads to ruptures at the point of passage of the ultrasonic wave.

All these phenomena occur when biological tissue is exposed to high-intensity ultrasound, and in certain conditions they are desirable, for example, in physiotherapeutic practice. During diagnosis, these effects do not occur as a result of the use of low-intensity ultrasound - no more than 50 mW*cm2. Structurally, devices for ultrasound medical diagnostics reliably protect the patient from the possible harmful effects of sound energy. However, recently, studies have increasingly appeared on the adverse effects of ultrasound on the patient. In particular, this applies to ultrasound examination in obstetrics. It has already been proven that ultrasound has an adverse effect on chromosomes, in particular it can lead to mutations in the fetus. In some countries, for example Japan, ultrasound examinations for pregnant women are performed only after a serious justification for the need for this examination. Undoubtedly, the impact of ultrasound on the doctor himself, who is under the influence of ultrasound for a long time. There are reports that over time the hand in which the doctor holds the sensor is affected.

Ultrasound technique in obstetrics.

The ultrasound technique in the pelvic area is quite simple and easy to perform. Before starting a woman’s examination, the doctor must familiarize herself in detail with the medical history and results of obstetric and gynecological data. No special preparation is required for ultrasound, but a good filling of the bladder is essential. In this regard, the patient is recommended to refrain from urinating 3-4 hours before the study or drink 3-4 glasses of water 1.5-2 hours before. If necessary, diuretics are prescribed or the bladder is filled through a catheter. A full bladder facilitates the examination of the uterus, as it lifts it and brings it to a central position, pushes aside intestinal loops, and is also a good acoustic environment for examining the pelvic organs.

Ultrasound is performed with the patient in a horizontal position on her back. Any contrast agent is applied to the skin of the anterior surface of the abdomen. Scanning is multi-positional, but must be performed in two planes (longitudinal and transverse) depending on the position of the sensor. The study begins with a longitudinal scan (sensor position in the sagittal plane) vertically above the pubis. The sensor is then moved in different planes to a horizontal position above the symphysis pubis (transverse scanning).

Longitudinal scanograms clearly reveal an oval-shaped echo-negative shadow of the bladder with smooth contours. Immediately behind it, towards the bottom, is the echo-positive structure of the pear-shaped uterus and vagina, delimited by two longitudinal lines extending at an angle from the uterus. It is difficult to identify the ovaries in this plane. On transverse scanograms, the uterus has the shape of an oval, on the sides of which echo-positive structures of rounded ovaries are revealed.

Ultrasound during pregnancy

Ultrasound in obstetrics turned out to be the most reliable and informative technique among other clinical methods in assessing certain aspects of the course of normal pregnancy and especially in its pathology.

Ultrasound examination of pregnant women is carried out according to strict clinical indications. During ultrasound of pregnant women, it is necessary to evaluate: the presence of a fertilized egg in or outside the uterus; determine their size and quantity; gestational age; presence of signs of impending miscarriage (its stage); the presence of an undeveloped pregnancy; hydatidiform mole; position, appearance and attachment of the fetus; umbilical cord condition; presence of signs of intrauterine fetal death; deformities (anomalies) of the fetus; condition of the placenta (normal, presentation, detachment); sex of the fetus; combination of pregnancy with uterine tumors.

During pregnancy, repeated ultrasound scans at different times can monitor the physiological development of the fetus. With echography, you can speak about the presence of pregnancy, starting from 2.5 - 3 weeks.

In the early stages of pregnancy, echograms clearly display the uterus (Figure 1), containing an oval-shaped fertilized egg with a fairly thick wall, the internal diameter of which is 0.5 cm, and the external diameter is up to 1.5 - 1.6 cm (3-4 weeks), including a bright band of villous chorion. By 6 weeks, the fertilized egg occupies ½ of the flat anatomical structures of the fetus. Fetal cardiac activity, a criterion for the correct development of pregnancy, is detected from 5–6 weeks, and motor activity from 6–7 weeks.

With the further development of normal pregnancy, the image of the fetus becomes clearer; by 10–11 weeks, the anatomical structures can be visualized: the skull, the torso (Fig. 2). The II and III trimesters are of particular importance, since during this period the formation and growth of the fetus, placenta, and accumulation of amniotic fluid occur. To assess the normal development of pregnancy

(Fig. 2) Fetus at 11 weeks. of pregnancy and term, starting from the 6th week, it is possible to measure the size of the fertilized egg, and subsequently the fetus and its anatomical organs. The most valuable information about the correct development of the fetus and the timing of pregnancy is provided by measurements of the distance from the sacrum to the head (KTR - sacral-parietal size), as well as in later stages of pregnancy, measurements of the biparietal size of the head (BPR), the average size of the femur, the average size of the chest at the level of the fetal heart, the size of the abdominal cavity at the level of the umbilical vein. There are specially developed tables on the dependence of the size of the fetus and its anatomical elements on the gestational age.

Ectopic pregnancy. With echography, the uterus is enlarged, the endometrium is thickened, and the fertilized egg is detected outside the uterine cavity. This condition can be clarified by repeated examination after 4–5 days, as well as by the presence of heartbeat and fetal movement outside the uterus. In differential diagnosis, one must keep in mind the possibility of uterine development anomalies.

Hydatidiform mole is a serious complication of pregnancy. Echograms show an enlarged uterus with or without a fertilized egg. In the uterine cavity, an echostructure of a small cystic nature, characteristic of a hydatidiform mole, resembling a “sponge”, is visible. A dynamic study reveals its rapid growth.

Multiple pregnancies can be diagnosed by ultrasound at different stages of pregnancy. On echograms, several fertilized eggs are detected in the uterine cavity, and in later stages, an image of several fetuses. Multiple pregnancies are often associated with various fetal deformities.

Fetal deformities are a common pathology of pregnancy. Classifications of various malformations of fetal organs and systems have been developed. Ultrasound makes it possible to confidently diagnose developmental anomalies such as hydrocephalus and anencephaly, in which there is no echographic display of the normal shape of the head. Other malformations of the fetus include abnormal position of the heart, abdominal hernia, ascites, osteogenesis disorders, polycystic kidney disease and hydronephrosis, etc.

Ultrasound of the placenta plays an important role. With echography, you can assess the maturity, size, location of the placenta, and monitor its development during pregnancy. The echographic image of the placenta appears as a thickened area of ​​the uterus of increased acoustic density with a fairly clear echo-positive border at the level of the amniotic fluid. Sometimes the placenta is difficult to distinguish from the myometrium, especially if it lies on the posterior wall of the uterus. Determining the exact location of the placenta, especially in relation to its internal os of the uterus, makes it possible to identify such a formidable complication as placenta previa. In this case, the placenta is located in the fundus of the uterus. Ultrasound examination can also reveal premature placental abruption and other pathological conditions. It is also important to point out that, according to clinical indications, ultrasound can be used during childbirth and the postpartum period in order to monitor the contractile activity of the uterus, as well as when examining newborns.

Conclusion

Currently, the ultrasound method has found wide diagnostic use and has become an integral part of the clinical examination of patients. In terms of absolute number, ultrasound examinations are very close to X-ray examinations.

At the same time, the boundaries of the use of echography have expanded significantly. Firstly, it began to be used to study those objects that were previously considered inaccessible for ultrasound assessment (lungs, stomach, intestines, skeleton), so that now almost all organs and anatomical structures can be studied sonographically. Secondly, intracorporeal studies have come into practice, carried out by introducing special microsensors into various cavities of the body through natural openings, by puncture into blood vessels and the heart, or through surgical wounds. This achieved a significant increase in the accuracy of ultrasound diagnostics. Thirdly, new directions for using the ultrasonic method have emerged. Along with routine routine examinations, it is widely used for the purposes of emergency diagnostics, monitoring, screening, and to monitor the implementation of diagnostic and therapeutic punctures.

Bibliography

Ultrasound diagnostics in gynecology. Demidov V.N., Zybkin B.I. Ed. Medicine, 1990.

Clinical ultrasound diagnostics. Mukharlyamov N.M., Belenkov

Yu.N., Atkov O.Yu. Ed. Medicine, 1987.

Ultrasound diagnostics in an obstetric clinic. Strizhakov A.T.,

Bunin A.T., Medvedev M.V. Ed. Medicine, 1990.

Obstetric Ultrasound – Dr. Joseph S. K. Woo (Hong Kong)

The more than 50-year history of ultrasound diagnostics has gone through different stages of its development: a period of complete denial, distrust, and reluctance of specialists to use the method, which was replaced by total enthusiasm and its revaluation. This stage is characterized by an adequate assessment of the capabilities and reliability of the results of ultrasound examination (US).

Ultrasound has become especially popular among patients and doctors in gynecology and obstetrics. It allows you to diagnose inflammatory diseases and developmental anomalies with high reliability, identify pelvic tumors, including during screening examinations, etc.

Advantages of the method and reasons for its popularity

The method became possible thanks to such basic properties of ultrasound as focusing, the ability to propagate in biological tissues and various reflections from dense environments of the body, including from the boundaries between them. Ultrasound examination is based on the principle of echolocation, which is the perception of reflected waves.

A special sensor device is connected to the device that generates ultrasonic waves. As one of the main elements, it includes a converter of the received information. Using the sensor, directional radiation occurs, the reflected signals are perceived and converted. As a result, a certain “picture” is displayed on the device’s display screen.

When passing through dissimilar tissues and cavities, varying degrees of attenuation and absorption of the wave, its partial reflection and refraction occur. When encountering homogeneous structures that have the same temperature and tissue density in all areas, ultrasound will be uniformly partially absorbed and equally uniformly reflected, creating an image of an organ with its more or less clear boundaries. If there is tissue in this environment with different characteristics, for example, a myomatous node in the muscular layer of the uterus (myometrium), the different intensity of the reflected signals forms a corresponding pathological formation with its boundaries on the display screen.

The ultrasound method has taken a strong position among other types of radiation diagnostics. Its popularity is explained by:

• the reliability and information content of the results obtained, which in most diseases coincide with the results of pathological studies (85-100%);
• accessibility of the procedure, its relative simplicity and non-invasiveness;
• the ability to obtain information in real time;
• the ability to carry out diagnostic and some therapeutic manipulations under visual control;
• absence of negative effects on tissues and the body as a whole during short-term research;
• low cost compared to other radiation diagnostic methods.

Principles of Ultrasound

Ultrasound diagnostics comes down to determining indications and goals, choosing the type and mode of examination, and preparing the patient.

Indications for use

In gynecology, ultrasound examination is recommended:

1. In case of menstrual irregularities and changes in their nature (heavy or, conversely, scanty, premature or delayed, etc.), which may be a sign of ovarian dysfunction, fibroids or other neoplasms, endometrial or cervical polyps, etc.
2. If menstrual pain is a symptom of endometriosis or inflammatory processes, or if there is a suspicion of inflammatory diseases of the uterus, fallopian tubes, ovaries or pelvic cavity.
3. When discharge and/or pain appears in the lower abdomen; they can occur with the development of tubal pregnancy, torsion of the fallopian tube, adhesions and inflammatory processes in the pelvis, tumors, and ovarian cysts.
4. For the purpose of diagnosing congenital anomalies of the uterus and appendages, pregnancy and dynamic monitoring of fetal development.
5. For a comprehensive diagnosis of the causes of infertility.
6. When taking oral contraceptives or if there are doubts about the correct installation of the intrauterine device in order to timely identify complications.
7. For urinary disorders, including urinary incontinence.
8. Before and after diagnostic curettage, medical or instrumental termination of pregnancy.
9. As a routine preventive examination for the purpose of early detection of benign and malignant tumors that are asymptomatic.

Types and modes

Various types of ultrasound in gynecology are performed using sensors of different shapes. Depending on the purposes and conditions of acoustic access, three types of studies are distinguished:

1. Vaginal ultrasound (through the vagina), which uses a standard probe. Visualization of the pelvic organs with this method is the clearest. It is performed with an empty bladder by inserting a sensor into the vagina. Transvaginal examination is used in most cases.
2. Transperitoneal or transabdominal ultrasound - the sensor is manipulated along the surface of the lower parts of the anterior abdominal wall with a full bladder. The technique is used mainly when there are formations of significant size in the pelvis.
3. Transrectal ultrasound - through the rectum. This type of diagnosis in gynecology is used only when examining virgins.

The choice of method and, accordingly, the type of sensor depends on the functional, anatomical and topographical features of the area under study or the targeted study of a specific organ or pelvic area.

Vaginal ultrasound

Transabdominal ultrasound

To conduct an ultrasound of the pelvic organs, equipment with various modes is used, which have different capabilities and have the corresponding purpose:

2D mode, or two-dimensional

It is characterized by the formation of a planar image of a gray-white color with many shades, that is, the organs are depicted in one plane (tomogram). In practical work, the method is used most often and is basic for any ultrasound examination.

This mode allows you to determine the shape and size of the uterus and its cavity, the cervical canal, the condition of their internal membrane, position in relation to other pelvic organs, the structure, shape and size of the uterus and ovaries, the presence of myomatous nodes, the condition of the ovaries, the size of the follicles and the corpus luteum , the presence of tumors in the pelvis and their size, the presence of fluid, as well as some pathological changes in the bladder when it is sufficiently full.

3D, or three-dimensional, but static mode

It is a synthesized volumetric image in several planes (two or more). This mode provides conditions for layer-by-layer study of the pelvic organs at different depths, as well as through “slices” in different planes and different thicknesses - from several centimeters to less than 1 millimeter.

If you do a gynecological ultrasound in 3D, this will make it possible to determine the sex of the child, congenital anomalies of the uterus (one-horned, two-horned, saddle-shaped), more accurate shapes and sizes of a benign or malignant tumor, endometrioid ovarian cysts, the degree of spread of endometriosis, the size of cervical tumors. You can also diagnose the presence of polyps and determine their size, the presence of intrauterine septa and synechiae (adhesions), the position of the intrauterine device, the ingrowth of its elements into the mucous membrane of the walls or prolapse from the uterine cavity.

4D mode

This is a three-dimensional image, but in dynamics. It allows you to see the movements of the fetus and the dynamics of its development, detail the vascular network of the pelvic organs by blood flow for differential diagnosis of inflammatory processes with tumors, determine their volume, exact size and even the nature and condition of the tumor, insufficiency of blood flow during necrosis of the myomatous node. You can also see the state of blood supply and varicose veins of the cavity and pelvic organs, and diagnose vein thrombosis.

In most devices, 3D and 4D modes are combined with the CID mode, which allows you to obtain a color image. In some cases, it becomes necessary to combine examination modes and ultrasound sensors, for example, transabdominal and transvaginal.

Patient preparation and optimal diagnostic timing

The doctor recommends to each patient individually when it is best to do a gynecological ultrasound. In standard cases, it is recommended in the first phase of the menstrual cycle, that is, 5-7 days after the start of menstruation. Optimally, this is the 3-5th day after its end, but not later than 7-10 days of the cycle. To assess ovarian function (formation of the corpus luteum, development of follicles), ultrasound is performed on days 8-10, 14-16 and 22-24 of the menstrual cycle.

The first diagnosis of pregnancy is possible from 3-4 weeks. When using a transvaginal sensor, it is possible at earlier stages. In order to identify asymptomatic pathological processes, especially tumors, all women are recommended to undergo preventive ultrasound of the pelvic organs annually or once every 2 years, and after 40 years - annually.

The study is carried out on an empty stomach after defecation and urination. The last meal should be no later than 8-12 hours before the procedure. If there are certain indications, the study is carried out regardless of the timing of the menstrual cycle:

• severe pain;
• intense bleeding;
• suspicion of ectopic pregnancy - tubal, ovarian, cervical;
• removal of the intrauterine device;
• presence of a foreign body, etc.

Recommended preparation for ultrasound in gynecology is aimed at maximally freeing the intestines from feces and gases. This is necessary to ensure optimal conditions for the passage of ultrasonic waves and their visualization on the screen. Therefore, appropriate preparations should begin 3-4 days before the upcoming study.

During these days, it is recommended to exclude from the diet indigestible and fatty foods and foods that contribute to gas formation in the intestines. The latter include legumes, fresh vegetables and fruits rich in fiber, brown bread, whole milk, carbonated drinks, coffee, high-calorie confectionery products (cakes, pastries)

To improve the digestion of food, you can take enzyme preparations - Festal, Creon, Panzinorm, Enzistal, and for better removal of gases - Espumisan, Carbolen, infusions of fennel or chamomile flowers. If you are prone to constipation, it is recommended to take laxatives. You should not use cleansing enemas, as this contributes to the retention of gases and air trapped with water in the lower intestines.

To fill the bladder, if an examination is to be performed through the anterior abdominal wall, it is recommended to drink 1-1.5 liters of liquid 1 hour before the procedure (depending on age and the presence of heart, vascular or kidney diseases).

Results of ultrasound examination in gynecology

When performing an ultrasound of the pelvic organs, a holistic picture of the organs being studied is created based on the comparison and interpretation of such characteristics as the localization and mobility of the organ or its parts, shape and size, structure, external and internal contours, location and anatomical relationship with neighboring structures or organs, indicators of functionality, the degree of conductivity of sound waves and the degree of their reflection (echogenicity), the absence or, conversely, the presence of effects characteristic or not characteristic of acoustic systems.

The examination protocol only describes the above indicators, but does not make a final diagnosis. Often, the conclusions of radiology specialists on the results of an ultrasound examination of the same patient, which were carried out in different diagnostic institutions, are different. This is due to the equipment used, the adequacy of the patient’s preparation for the procedure, the tasks set by the treating gynecologist, and the qualifications of the specialist.

As a rule, a diagnostician, describing the resulting “picture” of the pelvic cavity and its organs, can in his conclusion only make an assumption about certain deviations from the norm, but does not make a final diagnosis. Diagnostics is the prerogative of a gynecologist who formulates a diagnosis based on a comprehensive examination of the patient, including a general clinical examination, laboratory data, histological examination results, and additional consultations with the necessary specialists.

However, modern ultrasound technology, which makes it possible to obtain three-dimensional images of the pelvic organs at any depth and in various planes, especially in real time, provides the opportunity to solve complex diagnostic issues for the majority of gynecological diseases, and in most cases is a decisive factor in making a diagnosis .

Ultrasound examination (echography, scanning) is the only highly informative, safe, non-invasive method that allows dynamic monitoring of the condition of the fetus from the earliest stages of its development.

RATIONALE OF THE ULTRASOUND METHOD

Ultrasound diagnostics is based on the inverse piezoelectric effect. Ultrasound waves, reflected differently from organs and tissue structures, are captured by a receiver located inside the sensor and converted into electrical impulses. These pulses are reproduced on the screen in proportion to the distance from the sensor to the corresponding structure.

In obstetrics, two main methods are most widespread: transabdominal and transvaginal scanning. For transabdominal scanning, sensors (linear, convex) with a frequency of 3.5 and 5.0 MHz are used, for transvaginal scanning, sectoral sensors with a frequency of 6.5 MHz and higher are used. The use of transvaginal sensors makes it possible to establish the fact of pregnancy at an earlier stage, to study the development of the fetal egg (embryo and extraembryonic structures) with greater accuracy, and to diagnose most gross anomalies in the development of the embryo/fetus from the first trimester.

CELUSI

The main tasks of echography in obstetrics:
· establishing the fact of pregnancy, monitoring its progress;
· determination of the number of fertilized eggs;
· embryometry and fetometry;
· diagnosis of fetal development abnormalities;
· assessment of the functional state of the fetus;
· placentography;
· monitoring during invasive studies [chorionic villus biopsy, amniocentesis, cordocentesis, intrauterine surgery (fetosurgery)].

Objectives of ultrasound in the first trimester of pregnancy:

· establishment of intrauterine pregnancy based on visualization of the fertilized egg in the uterine cavity;
· exclusion of ectopic pregnancy;
· diagnosis of multiple pregnancy, type of placentation (bichorionic, monochorionic);
· assessment of the growth of the ovum (average internal diameter of the ovum, CTE of the embryo/fetus);
· assessment of the vital activity of the embryo (cardiac activity, motor activity);
· study of the anatomy of the embryo/fetus, identification of echomarkers of chromosomal pathology;
· study of extraembryonic structures (yolk sac, amnion, chorion, umbilical cord);
· diagnosis of pregnancy complications (threatened abortion, incipient abortion, complete abortion, hydatidiform mole);
· diagnosis of genital pathology (uterine fibroids, abnormalities of the uterine structure, intrauterine pathology, ovarian formations).

Objectives of ultrasound in the second trimester of pregnancy:

· assessment of fetal growth;
· diagnosis of developmental defects;
· study of markers of chromosomal pathology;
· diagnosis of early forms of FGR;
· assessment of the location, thickness and structure of the placenta;
· determination of the amount of OM.

Objectives of ultrasound in the third trimester of pregnancy:

· diagnosis of developmental defects with late manifestation;
· definition of ZRP;
· assessment of the functional state of the fetus (assessment of motor and respiratory activity, Doppler blood flow in the “mother-placenta-fetus” system).

INDICATIONS FOR Ultrasound

Ultrasound screening of pregnant women in our country is carried out at 10–14, 20–24 and 30–34 weeks.

RESEARCH METHODOLOGY AND INTERPRETATION OF ULTRASOUND RESULTS

Diagnosis of intrauterine pregnancy using ultrasound is possible from the earliest stages. From the 3rd week from conception, the fertilized egg begins to be visualized in the uterine cavity in the form of an echo-negative formation of a round or ovoid shape with a diameter of 5–6 mm. At 4–5 weeks, visualization of the embryo is possible - an echo-positive strip measuring 6–7 mm. The head of the embryo is identified from 8–9 weeks in the form of a separate anatomical formation of a round shape with an average diameter of 10–11 mm.

The most accurate indicator of gestational age in the first trimester is CTE (Fig. 11-1). In table 111 shows gestational standards for CTE for uncomplicated pregnancy.

Rice. 11-1. Coccyx-parietal size of the embryo.

The average error in determining the gestational age when measuring the ovum is ±5 days, CTE - ±2 days.

Assessment of the vital activity of the embryo in the early stages of pregnancy is based on recording its cardiac activity and motor activity. With ultrasound, cardiac activity of the embryo can be recorded from 4–5 weeks. Heart rate gradually increases from 150–160 per minute at 5–6 weeks to 175–185 per minute at 7–8 weeks, followed by a decrease to 150–160 per minute at 12 weeks. Motor activity is assessed from 7–8 weeks.

Table 11-1. Coccygeal-parietal dimensions of the embryo/fetus in the first trimester of pregnancy

From 4–5 weeks of pregnancy, a yolk sac is detected, the size of which varies from 6 to 8 mm. By 12 weeks, a physiological reduction of the yolk sac occurs. The absence of the yolk sac and its premature reduction are prognostically unfavorable signs.

Using transvaginal echography in the first trimester of pregnancy, severe congenital malformations are diagnosed - anencephaly, spinal cord herniation, skeletal anomalies, megacystis, etc. At 11–14 weeks, it is extremely important to identify echomarkers of chromosomal pathology - nuchal edema, hypoplasia/absence of the nasal bone, non-immune fetal hydrops, discrepancies between the CTE of the embryo and the gestational age.

When studying the growth and development of the fetus in the second and third trimesters of pregnancy, fetometry (measurement of the size of the fetus) is performed. The required scope of fetometry includes measurement of the biparietal size and circumference of the head, diameters or circumference of the abdomen, as well as the length of the femur (the length of the tubular bones is measured on both sides) (Fig. 11-2). Standard gestational indicators of fetometry are given in table. 11-2. Based on these parameters, it is possible to determine the estimated weight of the fetus.

Rice. 11-2. Fetometry.

a - measurement of biparietal size and head circumference;

b - measurement of abdominal circumference;

c - determination of the length of the femur.

Table 11-2. Fetometric parameters in the II and III trimesters of pregnancy

When carrying out echography in the II and III trimesters, the structures of the brain, skeleton, facial skull, internal organs of the fetus are examined: heart, lungs, liver, stomach, intestines, kidneys and adrenal glands, bladder.

Thanks to ultrasound, it is possible to diagnose most fetal anomalies. For a detailed assessment of the anatomy of the fetus, three-dimensional echography is additionally used, which allows one to obtain a three-dimensional image of the structure being studied.

The spectrum of echomarkers of fetal chromosomal pathology detected in the second trimester of pregnancy includes changes in various organs and systems: ventriculomegaly, cysts of the choroid plexus of the lateral ventricles, abnormal shapes of the skull and cerebellum (“strawberry”, “lemon”, “banana”), hyperechoic intestine, pyeloectasia, single umbilical cord artery, symmetrical form of FGR.

Using ultrasound, you can study the placenta in detail and obtain the necessary information about its location, thickness, and structure.

The localization of the placenta changes at different stages of pregnancy due to “migration” from the lower segment to the fundus of the uterus. If placenta previa is detected before 20 weeks of pregnancy, ultrasound should be repeated every 4 weeks.

The final conclusion about the location of the placenta should be made at the end of pregnancy.

An important indicator of the condition of the placenta is its thickness. Placental thickness follows a typical growth curve as pregnancy progresses. By 36–37 weeks, placental growth stops. Subsequently, during the physiological course of pregnancy, its thickness decreases or remains at the same level, amounting to 3.3–3.6 cm.

Ultrasound signs of changes in the placenta at different stages of pregnancy are determined by the degree of its maturity according to P. Grannum (Table 11-3).

Table 11-3. Ultrasound signs of the degree of maturity of the placenta

Changes in the structure of the placenta can be in the form of cysts, which are visualized as echo-negative formations of various shapes and sizes.

Ultrasound diagnosis of PONRP is based on identifying the echo-negative space between the uterine wall and the placenta.

Ultrasound is also used to diagnose the consistency of a postoperative scar on the uterus. The consistency of the scar is evidenced by the homogeneous tissue structure and smooth contours of the lower segment of the uterus, its thickness is at least 3–4 mm. The failure of a uterine scar is diagnosed based on the identification of a defect in the form of a deep niche, thinning in the area of ​​the intended scar, and the presence of a large number of hyperechoic inclusions (connective tissue).

Ultrasound provides valuable information about the condition of the cervix during pregnancy and the risk of preterm birth. With transvaginal echography, which has significant advantages over digital examination of the cervix and transabdominal echography, it is possible to determine the length of the cervix along its entire length, the condition of the internal pharynx, and the cervical canal (Fig. 11-3).

Rice. 11-3. Study of the condition of the cervix with transvaginal echography.