Ultrasound examination (or sonography) is one of the most modern, accessible, informative methods of instrumental diagnostics. The main advantage of ultrasound is its non-invasiveness, i.e., in the process of examination, the skin and other tissues, as a rule, do not have a mechanical damaging effect. This type of diagnosis is not associated with pain or other discomfort for the patient. Unlike conventional radiography, ultrasound does not use radiation that is dangerous to the human body. From this article you will learn what ultrasound is, how it is performed and much more.
The principle of operation of ultrasound
Sonography allows specialists to notice even the smallest changes in the organ and detect the disease at the stage at which clinical symptoms have not yet developed. As a result, in a patient who underwent an ultrasound procedure in a timely manner,the chances of an absolute recovery increase many times over.
The first successful studies of patients using ultrasound were carried out in the mid-50s of the 20th century. Previously, the principle was used only in military sonars to detect underwater objects.
To study various internal organs, high-frequency sound waves - ultrasound - are used. Since the "picture" is displayed on the screen in real time, this gives doctors the opportunity to identify a number of processes that occur in the patient's body, in particular the movement in the blood vessels.
Ultrasonic research from the point of view of physics is based on the piezoelectric effect. In the role of piezoelectric elements, which alternately work as a transmitter and receiver of a signal, single crystals of quartz or barium titanate are used. When exposed to high-frequency sound vibrations, charges are formed on the surface, and during the supply of current to the crystals, mechanical vibrations are created, which are accompanied by ultrasound radiation. These fluctuations are due to the rapid change in the shape of single crystals.
The so-called piezo transducers are considered the basis of diagnostic devices. They are the basis of sensors, where, in addition to crystals, a special sound-absorbing wave filter is also provided, an acoustic lens designed to focus the ultrasound device on the desired wave.
When reaching the boundary of zones with different impedance, the beam of waves noticeably changes. Some of them continue to move in the previously determined direction, and the other partreflected. The reflection coefficient will depend on the difference in the resistance index of the two media.
And now it's worth considering in more detail what kind of ultrasound is.
Ultrasound of the heart
For studies of the heart, as well as blood vessels, a type of ultrasound is used, such as echocardiography. With an assessment of the general state of blood flow, the Doppler technique allows you to see changes in the heart valves, determine the size of the atria and ventricles, as well as changes in the structure and thickness of the myocardium, that is, the heart muscle. During the course of the diagnosis, it is also possible to examine the areas of the coronary arteries.
The intensity of the narrowing of the lumen of the vessels can be detected by constant-wave Doppler sonography. As for the pumping function, it is assessed using a Doppler pulse study. Regurgitation, that is, the movement of blood through the valves in the opposite direction to the physiological, can be detected using Doppler color mapping.
Echocardiography diagnoses such serious diseases as the latent form of coronary artery disease and rheumatism, as well as notice neoplasms. There are no contraindications to this diagnostic procedure. If there are any identified chronic pathologies in the cardiovascular system, it would be advisable to undergo echocardiography at least once a year.
Ultrasound of the abdomen
What else is an ultrasound? This should, of course, include an examination of the abdomen. Abdominal ultrasound is most commonly usedto control the condition of the liver, spleen, gallbladder, main vessels and kidneys. It should be noted that for ultrasound examination of the abdominal cavity, as well as the small pelvis, the most optimal frequency is considered to be in the range of 2.5-3.5 MHz.
Ultrasound of the kidneys
So, we continue to consider what kind of ultrasound is. Thanks to ultrasound of the kidneys, it is possible to detect cystic neoplasms in the patient, the presence of calculi (that is, stones), and the expansion of the renal pelvis. This diagnosis of the kidneys is necessarily carried out in case of hypertension.
Thyroid ultrasound
Speaking about what types of ultrasound are, we should mention the thyroid gland. It is indicated in the case of an increase in this organ and the appearance of a nodular neoplasm, as well as when there is discomfort, pain in the neck area. This study is mandatory for all residents living in ecologically disadvantaged areas and regions, as well as in regions where the amount of iodine in drinking water is very low.
Pelvic ultrasound
Such a diagnosis is necessary to assess the condition of all organs in the female reproductive system. This ultrasound allows you to detect pregnancy at an early stage. In men, this method provides an opportunity to identify various pathological changes in the prostate gland.
Breast ultrasound
What are ultrasound organs? One of these is an ultrasound of the mammary glands, which is used to identify the nature of the neoplasm in the breast. To ensure tight contactBefore the procedure, a gel is applied to the surface of the skin with a special sensor, which contains styrene compounds, as well as glycerin.
Ultrasound during pregnancy
Scanning today is widely used in obstetrics, as well as perinatal diagnostics - the study of the baby at different times. It allows you to determine the pathology of the development of the child. During pregnancy, it is strongly recommended to undergo an ultrasound examination at least three times.
On ultrasound, a gynecologist is able to detect some developmental anomalies:
- non-infection of the hard palate in the fetus;
- hypotrophy;
- polyhydramnios, oligohydramnios;
- placenta previa.
It is very problematic to do without ultrasound during the diagnosis of multiple pregnancy, as well as in determining the location of the fetus.
Methods of the procedure
Considering what types of gynecological ultrasounds are, we should mention those types that differ from each other in terms of implementation methods. Ultrasound examination of the pelvis is considered basic in the diagnosis of diseases in the field of gynecology. Therefore, if you are wondering what kind of ultrasound in gynecology are, this should be included here.
With this diagnosis, the structure of the uterus, fallopian tubes, the structure and size of the bladder, the size of the ovary, and the blood supply to the genital organs are checked. But what are pelvic ultrasounds depending on the method of conducting? Research can be conducted:
- Transabdominally. Implementedexternal method through the wall of the abdomen, which is why it is most suitable for virgins, pregnant women and patients with poorly developed genital external organs. If you don’t know what ultrasounds are during pregnancy, then this should be included here.
- Transvaginally. The sensor with which the picture is generated is inserted into the vagina. There is some discomfort with this method.
- Transrectally. During this, the transducer is inserted directly into the rectum. The method is informative, unpleasant, therefore it is used only if the above two turned out to be impossible.
Advantages and disadvantages of ultrasound
The benefits are as follows:
- harmlessness;
- cheap;
- safety for children and pregnant women;
- short duration of the study;
- no invasive intervention;
- receiving information in real time;
- obtaining 3D images and 4D video frames.
Disadvantages of ultrasound are as follows:
- limiting image sharpness by sensor area;
- low res;
- the need for preparation before ultrasound of the abdominal cavity (diet, the use of carminative drugs);
- a large number of different interferences in the study due to the heterogeneity of the environment of the human body.
In addition, the dimensions of the tumor formations under study are presented on a section whose diameter dependsfrom the angle of the sensor. Possible diagnostic errors in assessing tumor growth: with direct penetration of waves, only one size is determined, and in case of a deviation of several degrees, this section size increases significantly.
