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Ultrasound scanning is by far one of the most popular and safe diagnostic methods. Using this method of examination, it is possible to assess the state of almost all body systems, from the digestive to the reproductive. Scanning has no side effects, does not cause pain and can be repeated if necessary, which is a significant plus. The results obtained help physicians to identify the pathology at an early stage and provide effective treatment in time.
What is an ultrasound scanner
An ultrasound machine (ultrasound scanner) is a diagnostic tool equipped with a sensor that emits and receives high-frequency sound waves. The principle of its operation is based on the use of high-frequency sound waves to obtain images of the internal structures of the body. Due to the absence of ionizing radiation, ultrasound scanning is allowed during pregnancy and is used for prenatal care.
Ultrasound scanning is used in obstetric practice to assess the development of the fetus and identify possible pathological changes.
Ultrasound guidance helps with certain types of manipulations: punctures, intra-articular injections, biopsies. There are also special intraoperative sensors that are used during surgical operations.
An ultrasound doctor is a specialist who conducts an ultrasound scan of organs and systems to detect changes in them. The doctor examines the resulting image in real time, records the necessary data in the study protocol and issues a conclusion. If the examination reveals pathological changes, the ultrasound specialist makes a conclusion about what disease they may correspond to. The final diagnosis is made by the patient’s attending physician.
Ultrasonic waves easily pass through soft tissues and liquids and are reflected from denser structures. Thus, by analyzing the changes in the acoustic resistance of various tissues, an image of the internal organs can be simulated on the screen of the ultrasound machine. The main element of the ultrasonic device is a transducer, which, using a piezoelectric crystal, converts an electrical signal into high-frequency sound (0,5-15 MHz). This part in ultrasonic devices is called a transducer or simply a sensor. Scanning is provided by successive generations of ultrasonic waves and registration of echo signals from different directions within the radiation pattern of the sensor. The cumulative analysis of the received echo signals makes it possible to build an acoustic image of deep tissues and organs on the monitor screen of an ultrasound machine. In this case, the brightness of each point is directly dependent on the intensity of the echo signal. The image on the screen is usually represented by shades of gray or a color palette that reflects the acoustic structure of tissues. On gray-scale machines, stones appear bright white, while fluid-containing masses, such as cysts, appear black. The higher the radiation frequency of the sensor, the higher the resolution of the ultrasonic device, so for expert-class models with 18-20 MHz sensors, the resolution reaches 0,7 mm. The use of multi-frequency sensors with a wide band of operating frequencies gives a significant increase in resolution in the near and middle (in depth) zone. Modification of digital broadband scanning – multibeam scanning, allows you to highlight the studied elements and structures with more contrast.
For diagnostic purposes, the signal from an ultrasound scanner is typically between 2 and 18 megahertz (MHz). The choice of sensor for each study is carried out taking into account the depth and nature of the position of the organ.
Ultrasonic transducers with a higher scan rate provide a high resolution image of the region of interest. The depth of penetration of ultrasound into the tissues of the body is inversely proportional to its frequency. Therefore, high-frequency sensors are mainly used to study superficially located structures – the thyroid gland, mammary glands, small joints and muscles, as well as to study blood vessels. To study deeply located organs (organs of the abdominal cavity and retroperitoneal space, genitourinary and reproductive systems), sensors with a lower frequency but a greater scanning depth are usually used.
Here are some key points regarding ultrasound scanning:
- this scan is safe and widely used in medical practice;
- allowed during pregnancy;
- used to diagnose and monitor the effectiveness of treatment;
- most types of ultrasound diagnostics do not require special training;
- carried out over a relatively short period of time.
Where is ultrasonic scanning used?
Currently, ultrasound examination can be used for screening, primary diagnosis, control of therapeutic and diagnostic measures, and in some cases even as the final method of diagnosis.
The areas of application of ultrasound in medicine are extremely wide. For diagnostic purposes, it is used to detect diseases of the abdominal organs and kidneys, pelvic organs, thyroid gland, mammary glands, heart, blood vessels, in obstetric and pediatric practice. Ultrasound is also used as a method for diagnosing emergency conditions requiring surgical intervention.
With the help of ultrasound, various volumetric formations of both superficially located tissues and internal organs are detected with a sufficiently high accuracy.
In gastroenterology, ultrasound is used to evaluate the abdominal organs. Examination of the abdominal organs is recommended to be performed on an empty stomach. Ultrasound examination is a widely used method for examining gastroenterological patients and allows diagnosing a fairly large number of pathological changes, such as: diffuse changes in the parenchyma of the liver and pancreas, stones in the gallbladder, the presence of anomalies of internal organs, malignant and benign neoplasms.
With the help of ultrasound, it is possible to detect the presence of free fluid in the abdominal cavity and pericardium, which can play a decisive role in the medical tactics of the surgeon and traumatologist.
Ultrasound scanning helps diagnose soft tissue, muscle, tendon, and joint problems. An ultrasound method for studying the musculoskeletal system is indispensable in the diagnosis of various types of tendon and ligament injuries, including sports injuries and post-traumatic conditions.
Ultrasound diagnosis of the structure and function of the heart is called “echocardiography” (EchoCG). During this study, the dimensions of the heart and its individual structures, the presence and volume of fluid in the pericardial cavity, the condition of the heart valves, as well as blood flow in the heart and great vessels are evaluated.
Ultrasound scanning is used in ophthalmology. Ultrasound methods make it possible to visualize the contents of the eyeball (including in the absence of transparency of optical media) and the orbit. The study allows you to detect opacities in the vitreous body, retinal detachment, intraocular tumors and neoplasms of the orbit, to clarify the localization of foreign bodies, including X-ray negative ones (stone, glass, wood). The ultrasound method is also used to measure the depth of the anterior chamber of the eye, the thickness of the lens, control the degree of stretching of the eyeball in myopia, etc.
Currently, ultrasound sonography has become the main method for examining the brain in newborns and young children. The method of sectoral scanning of the brain through the large fontanel in a newborn child is called “transfonticular sectoral echoencephalography” or “neurosonography” (NSG). Ultrasound scanning of the brain of infants allows you to visualize the central structures of the brain and determine the size of the lateral ventricles.
Ultrasound examination of the pelvic organs in women provides important information about the structure of the uterus and ovaries. In obstetrics and gynecology, ultrasound is performed both transabdominally and transvaginally. The use of a transvaginal transducer makes it possible to more clearly visualize the pelvic organs, especially in overweight women. With transvaginal ultrasound of the pelvic organs, filling the bladder is not required.
Ultrasound is used in the diagnosis of fertility function. The method is used for dynamic monitoring of the growth of the dominant follicle, the effectiveness of ovulation stimulation. Under the control of ultrasound scanning, the follicle is punctured during egg collection.
Ultrasound examination allows you to get information about the presence, location and duration of pregnancy, to recognize pregnancy in the early stages. The use of ultrasound makes it possible to establish an undeveloped pregnancy, an ectopic pregnancy. With the help of ultrasound examination, it is possible to diagnose developmental disorders and diseases of the fetus in time, as well as pathological changes in the placenta, umbilical cord and cervix.
In men, pelvic ultrasound can visualize the prostate gland and seminal vesicles. During ultrasound scanning, the shape, size of the gland, as well as changes in the structure and the presence of pathological formations, are determined. More accurate data can be obtained using the transrectal ultrasound scanning method.
Ultrasound diagnostics allows differentiating various vascular pathologies. Vascular ultrasound is an accessible, widespread, relatively simple diagnostic method that is often used to diagnose lesions of arteries and veins. This method helps to identify atherosclerotic plaques, blood clots, aneurysms, anomalies in the course of blood vessels. Vascular ultrasound is often used in neurology to assess the blood supply to the brain. Duplex scanning of blood vessels is a universal and informative method that allows you to study both the structure of the walls of the vessel and the features of the passage of blood through it.
Modern ultrasound equipment allows scanning with a large number of frames per second, which ensures high information content of the study. According to the results of ultrasound, one can judge the location, shape and size of the organ under study, the homogeneity or heterogeneity of tissues. This makes it possible not only to identify any formations, but also to assess the structure of the organ.
The improvement of computer technologies, the use of digital signal processing and analysis methods, has significantly expanded the capabilities of ultrasound scanners. Modern devices are equipped with many additional programs and scanning modes that give the specialist new tools for detecting pathological changes at an early stage. The use of digital echo signal processing and image optimization techniques can reduce the number of artifacts, eliminate distortion, and significantly increase contrast and resolution. This contributes to a more accurate ultrasound diagnosis.
How is the inspection performed using the device
The decision on the possibility of conducting an ultrasound examination and a specific method of ultrasound diagnostics is made by the doctor of ultrasound diagnostics, taking into account the validity of the appointment, the presence of medical indications (contraindications), and the risk of complications.
When a pathology is detected, the doctor expands the boundaries of the anatomical region subject to ultrasound examination, indicating the reason for the expansion and the result of the study in the protocol.
During the examination, the patient lies on the couch, a transparent gel is applied to his skin in the study area, after which the doctor, moving a special sensor, sees an image of the internal organs and systems being examined on the monitor.
Gynecological ultrasound is performed by transabdominal access with a full bladder, and with transvaginal access – with an empty bladder. Ultrasound of the prostate gland is performed by transabdominal access when the bladder is full and by transrectal access when the bladder is empty.
Scan results
According to the results of the study, the doctor of ultrasound diagnostics forms a protocol in paper or electronic form.
The protocol must contain, among other things:
- significant information for interpreting the results of the ultrasound examination;
- a detailed description of the results of the study with the necessary measurements (including a description of the identified pathological changes and development options);
- ultrasound signs of diseases, injuries, conditions, malformations (including in utero), non-specific changes with a standardized scale for evaluating results.
The protocol is accompanied by images obtained during the ultrasound. These documents are attached to the patient’s medical records.
At the request of the patient (including in electronic form), he is given a copy of the protocol.