When the ultrasound appeared in the USSR. Ultrasonic research method

It is difficult for modern patients to imagine that not so long ago, doctors did without such a diagnostic method as ultrasound. Ultrasound has revolutionized medicine, giving doctors a highly informative and safe way to examine patients.

In just half a century, which has a history of ultrasound medicine, ultrasound has become the main assistant in the diagnosis of most diseases. How did this method appear and develop?

The first research of ultrasonic waves

People guessed the presence of sound waves in nature that were not perceived by humans for a long time, but the Italian L. Spallanzani discovered “invisible rays” in 1794, proving that a bat with closed ears ceases to navigate in space.

The first scientific experiments with ultrasound began to be carried out in the XIX century. In 1822, the Swiss scientist D. Colladen was able to calculate the speed of sound in water by immersing an underwater bell in Lake Geneva, and this event predetermined the birth of sonar.

In 1880, the Curie brothers discovered the piezoelectric effect that occurs in a quartz crystal under mechanical action, and 2 years later, an inverse piezoelectric effect was generated. This discovery formed the basis for the creation of a piezoelectric transducer of ultrasound - the main component of any ultrasound equipment.

XX century: sonar and metal detection

The beginning of the 20th century was marked by the development of sonar — the detection of objects under water using an echo. We owe the creation of the first echo sounders to several scientists from different countries at once: the Austrian E. Bem, the Englishman L. Richardson, the American R. Fessenden. Thanks to sonars that scanned the depths of the sea, it became possible to find underwater obstacles, sunken ships, and during the years of World War I - enemy submarines.

Another ultrasonic direction was the creation in the early 30s of flaw detectors to search for flaws in metal structures. Ultrasonic metal detection has found its place in industry. One of the founders of this method was the Russian scientist S.Ya. Sokolov.

Echolocation and metal detection methods laid the foundation for the first experiments with living organisms, which were carried out by industrial devices.

Ultrasound: a step into medicine

Attempts to put ultrasound at the service of medicine date back to the 30s of the 20th century. Its properties began to be used in physiotherapy of arthritis, eczema and a number of other diseases.

The experiments that began in the 40s were already aimed at using ultrasonic waves as a tool for diagnosing neoplasms. Success in research was achieved by the Vienna neuropsychiatrist C. Dussik, who in 1947 introduced a method called hypersonography. Dr. Dussik managed to detect a brain tumor by measuring the intensity with which an ultrasound wave passed through the patient’s skull. It is this scientist who is considered one of the founders of modern ultrasound diagnostics.

A real breakthrough in the development of ultrasound scanning occurred in 1949, when a US scientist D. Howry constructed the first medical scanning device. This and subsequent works of Hauri little resembled modern appliances. They represented a reservoir with a liquid in which the patient was placed, forced to sit still for a long time, while an abdominal scanner moved around him - a somoscope.

Around the same time, the American surgeon J. Wilde created a portable device with a movable scanner that produced a real-time visual image of tumors. He called his method sonography.

In subsequent years, ultrasound scanners were improved, and by the mid-60s they began to take on a form close to modern equipment with manual sensors. At that time, Western doctors began to obtain licenses for using the ultrasound method in practice.

Experiments on the use of ultrasound were carried out by Soviet scientists. In 1954, a specialized department headed by Professor L. Rosenberg appeared at the Acoustics Institute of the USSR Academy of Sciences.

The release of domestic ultrasound scanners was established in the 60s at the Research Institute of Instruments and Equipment. Scientists have created a number of models intended for use in various medical fields: cardiology, neurology, ophthalmology. But all of them remained in the experimental status and did not receive a “place under the sun” in practical medicine.

By the time Soviet doctors began to show interest in ultrasound diagnostics, they already had to take advantage of the achievements of Western science, because by the 90s of the last century, domestic developments were hopelessly outdated and behind the times.

Modern technologies in ultrasound

Methods of ultrasound diagnostics continue to develop actively. The usual two-dimensional visualization is being replaced by new technologies that make it possible to obtain a three-dimensional image, “travel” inside the body cavities, and recreate the appearance of the fetus. For instance:

1. 3D ultrasound  - Creates a 3D image from any angle.
2. Echo Contrast -Ultrasound using intravenous contrast containing microscopic gas bubbles. It features high diagnostic accuracy.
3. Fabric, or 2nd harmonic (THI)  - Technology with improved image quality and contrast, indicated for overweight patients.
4. Sonoelastography -Ultrasound using an additional factor - pressure, which helps to determine pathological changes by the nature of tissue contraction.
5. Ultrasound tomography  - a technique similar in terms of informativeness of CT and MRI, but at the same time completely harmless. It collects voluminous information followed by computer image processing in three planes.
6. 4 D- ultrasound  - technology with the ability to navigate inside the vessels and ducts, the so-called "inside view". The image quality is similar to endoscopic examination.

In the year 1794, Spallanzani noticed that if a bat plugs its ears, it loses orientation, and he suggested that orientation in space is carried out by emitted and perceived invisible rays.

In laboratory conditions, ultrasound was first obtained in 1830 by the Curie brothers. After the Second World War, Holmes, on the basis of the principle of a sonar device used in the submarine fleet, constructed diagnostic devices that were widely used in obstetrics, neurology, and ophthalmology. Subsequently, the improvement of ultrasound devices has led to the fact that this method has now become the most common when visualizing parenchymal organs. The diagnostic procedure is short, painless and can be repeated many times, which allows you to monitor the treatment process.

What determines ultrasound?

Ultrasound method  It is intended for the distant determination of the position, shape, size, structure and movement of organs and tissues of the body, as well as for identifying pathological foci using ultrasound radiation.

Ultrasonic waves are mechanical, longitudinal vibrations. environment, with an oscillation frequency of over 20 kHz.

Unlike electromagnetic waves (light, radio waves, etc.), the propagation of U-sound requires a medium - air, liquid, tissue (it does not propagate in a vacuum).

Like all waves, U-sound is characterized by the following parameters:

• Frequency - the number of complete oscillations (cycles) over a period of 1 sec. Units of measurement are hertz, kilohertz, megahertz (Hz, kHz, MHz). One hertz is an oscillation of 1 sec.
• wavelength is the length that one oscillation occupies in space. Measured in meters, cm, mm, etc.
• The period is the time required to obtain one full cycle of oscillations (sec, milliseconds, microseconds.).
• Amplitude (intensity - wave height) - determines the energy state.
• The propagation velocity is the speed with which the Y-wave travels in the medium.

The frequency, period, amplitude and intensity is determined by the sound source, and the propagation velocity by the medium.

The propagation velocity of ultrasound is determined by the density of the medium. For example, in air, the speed is 343 m per second, in the lungs - more than 400, in water - 1480, in soft tissues and parenchymal organs from 1540 to 1620, and in bone tissue ultrasound travels more than 2500 m per second.

The average speed of ultrasound propagation in human tissues is 1540 m / s - most ultrasound diagnostic devices are programmed for this speed.

The basis of the method is the interaction of ultrasound with human tissues, which consists of two components:

The first is the emission of short ultrasonic pulses directed into the tissue under study;

The second one is image formation based on signals reflected by tissues.

Piezoelectric effect

To obtain ultrasound, special transducers are used - sensors or transducers that convert electrical energy into ultrasound energy. Getting ultrasound is based on inverse piezoelectric effect. The essence of the effect is that when a voltage is applied to the piezoelectric element, its shape changes. In the absence of electric current, the piezoelectric element returns to its original shape, and when the polarity changes, the shape will again change, but in the opposite direction. If an alternating current is applied to the piezoelectric element, the element will begin to oscillate at a high frequency, generating ultrasonic waves.

When passing through any medium, an attenuation of the ultrasonic signal will be observed, which is called impedance (due to the absorption of energy by the medium). Its value depends on the density of the medium and the speed of propagation of ultrasound in it. Having reached the boundary of two media with different impedances, the following changes occur: part of the ultrasound waves is reflected and follows back towards the sensor, and part continues to propagate further, the higher the impedance, the more reflected ultrasound waves. The reflection coefficient also depends on the angle of incidence of the waves - the right angle gives the greatest reflection.

(at the interface between air and soft tissues, almost complete reflection of ultrasound occurs, and therefore, to improve the conduct of ultrasound in the tissues of the human body, they use connecting media - gel).

The returning signals cause oscillations of the piezoelectric element and are converted into electrical signals - direct piezoelectric effect.

Ultrasonic sensors use artificial piezoelectrics such as zirconate or lead titanate. They are complex devices and, depending on the way the image is scanned, are divided into sensors for devices slow  scans are usually singleton and quick  real-time scans - mechanical (multi-element) and electronic. Depending on the shape of the resulting image, they are distinguished sectoral, linear and convex (convex)  sensors. In addition, there are intracavitary (transesophageal, transvaginal, transrectal, laparoscopic and intraluminal) sensors.

Advantages of fast scanning devices: the ability to evaluate the movements of organs and structures in real time, a significant reduction in time to conduct research.

Sector Scan Benefits:

• a large viewing area at a depth that allows you to cover the entire organ, for example, the kidney or the embryo of the child;
• the ability to scan through small “transparency windows” for ultrasound, for example, in the intercostal space when scanning the heart, when examining the female genital organs.

Disadvantages of sector scanning:

• the presence of a "dead zone" 3-4 cm from the surface of the body.

The benefits of linear scanning:

• insignificant "dead zone", which makes it possible to examine the surface organs;
• the presence of several tricks along the entire length of the beam (the so-called dynamic focusing), which provides high clarity and resolution throughout the depth of scanning.

Disadvantages of linear scanning:

• a narrower field of view at depth compared to sector scanning, which does not allow you to "see" the entire organ at once;
• the impossibility of scanning the heart and difficulty scanning the female genital organs.

According to the principle of operation, ultrasonic sensors are divided into two groups:

• Echo pulse - to determine the anatomical structures, their visualization and measurement.
• Doppler - allow you to get a kinematic characteristic (assessment of the speed of blood flow in the vessels and heart).

The basis of this ability is the Doppler effect - a change in the frequency of sound received when the blood moves relative to the vessel wall. In this case, sound waves emitted in the direction of motion are compressed, as it were, increasing the frequency of sound. The waves radiated in the opposite direction, as it were, are stretched, causing a decrease in the frequency of sound. A comparison of the initial frequency of the ultrasound with the changed one allows us to determine the Doppler shift and calculate the speed of blood movement in the lumen of the vessel.

Thus, the pulse of ultrasonic waves generated by the sensor propagates through the tissue, and reaching the boundary of tissues with different densities is reflected in the direction of the transducer. The received electrical signals are fed to a high-frequency amplifier, processed in an electronic unit and displayed as:

• one-dimensional (in the form of a curve) - in the form of peaks on a straight line, which allows you to estimate the distance between the layers of tissues, for example in ophthalmology (A-method “amplitude”), or to study moving objects, for example, the heart (M-method).
• two-dimensional (B-method, in the form of a picture) image, which allows you to visualize various parenchymal organs and the cardiovascular system.

To obtain an image in ultrasound diagnostics, ultrasound is used, which is emitted by the transducer in the form of short ultrasonic pulses (pulsed).

To characterize pulsed ultrasound, additional parameters are used:

• The pulse repetition rate (the number of pulses emitted per unit time - second) is measured in Hz and kHz.
• Impulse duration (time duration of one impulse), measured in sec. and microseconds.
• Ultrasound intensity is the ratio of the wave power to the area over which the ultrasonic flow is distributed. It is measured in watts per square centimeter and, as a rule, does not exceed 0.01 W / sq.cm.

In modern ultrasonic devices, ultrasound with a frequency of 2 to 15 MHz is used to obtain an image.

In ultrasound diagnostics, sensors with frequencies of 2.5 are usually used; 3.0; 3.5; 5.0; 7.5 megahertz. The lower the frequency of ultrasound, the greater the depth of its penetration into tissues, ultrasound with a frequency of 2.5 MHz penetrates up to 24 cm, 3-3.5 MHz - up to 16-18 cm; 5.0 MHz - up to 9-12 cm; 7.5 MHz to 4-5 cm. For the study of the heart, a frequency of 2.2-5 MHz is used, in ophthalmology - 10-15 MHz.

The biological effect of ultrasound

and its safety for the patient is constantly debated in the literature. Ultrasound can cause biological effects through mechanical and thermal influences. The attenuation of the ultrasonic signal is due to absorption, i.e. transforming the energy of an ultrasonic wave into heat. Tissue heating increases with increasing intensity of the emitted ultrasound and its frequency. A number of authors note the so-called cavitation is the formation of pulsating bubbles in a liquid filled with gas, steam, or a mixture thereof. One of the causes of cavitation can be an ultrasonic wave.

Studies related to the effects of ultrasound on cells, experimental work on plants and animals, as well as epidemiological studies have made the following statement to the American Institute of Ultrasound:

“No confirmed biological effects have been reported in patients or persons working on the device caused by exposure to ultrasound, the intensity of which is typical of modern ultrasound diagnostic systems. Although there is a possibility that such biological effects may be identified in the future, current evidence indicates that the patient’s benefit with the prudent use of diagnostic ultrasound outweighs the potential risk, if any. ”

To study which organs and systems is the ultrasound method used?

• Parenchymal organs of the abdominal cavity and retroperitoneal space, including pelvic organs (embryo and fetus).
• The cardiovascular system.
• Thyroid and mammary glands.
• Soft tissue.
• The brain of a newborn.

What criteria are used in ultrasound studies:

1. CONTOURS - clear, even, uneven.
2. ECHO STRUCTURE:

• Liquid;
• Semi-liquid;
• Tissue - more or less density.

Paul G. Newman, MD

Grace S. Rosicky, MD, Member of the Scientific Society of the American College of Surgery

Paul Newman MD, Grace S. Rozycki MD, FACS)

Department of Surgery, Emory University School of Medicine, Grady Memorial Hospital, Atlanta, Georgia

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Paul G. Newman, MD

Department of Surgery

Emory University School of Medicine

Thomas K. Glenn Memorial Building

69 Butler Street, SE

Atlanta, GA 30303

Over the past 40 years, ultrasound has become an important diagnostic technique. His potential as a leader in imaging medical diagnostics was recognized in the 1930s and 1940s when Theodore Dussik and his brother Friedrich tried to use ultrasound to diagnose brain tumors. However, it was not until the 1970s that the work of these and other pioneers in ultrasound research really paid off.

Along with technological advances, ultrasound has progressed from a large, bulky machine that reproduces sub-optimal images to a portable, easy-to-use, and sophisticated instrument. Such evolution required a close unity of physics, physiology, medicine, technology, and management. This article lists the major advances in the evolution of ultrasound and highlights some of the outstanding contributions made by ultrasound pioneers to this field.

ALFRED LORD TENNYSON

MILESTONES IN SOUND (MILESTONES IN SOUND)

Long before modern scientists, the usefulness of ultrasound in the field of medicine was considered, a step towards this was the study of sound. Nineteenth-century requests for measuring the speed of sound in water paved the way for sonar (sonar navigation and distance measurement (SONAR - SOund Navigation And Ranging). Jean-Daniel, Swiss physicist and Charles Sturm, mathematician, performed some of the earliest experiments in this In the struggle for the annual prize from the Royal Academy of Sciences in Paris in 1826 (Academie Royale des Sciences of Paris), Colladon determined the speed of sound in water in order to help confirm his data on the compressibility of liquids. Colladon, regarded as the birth of modern sonar, it consisted of a blow to an underwater bell in Lake Geneva with the same burning of gunpowder.A flash of gunpowder was observed by Colladon at a distance of 10 miles, he also heard the sound of a bell using an underwater auditory tube. events, Colladon calculated the speed of sound in Lake Geneva, it was equal to 1435 m / s, the difference with modern calculations is only 3 m / s.

Later, in 1877, John William Strutt (also known as Lord Rayleaf) published The Theory of Sound, which became the foundation for the science of ultrasound. His contribution was considered so significant that Lord Raliffe was appointed to the UK Chamber of Inventions and Research, a body that monitored sonar advancement during the First World War.

PIEZOELECTRICITY

In 1880, Pierre and Jacques Curie made an important discovery, which ultimately led to the development of a modern ultrasonic transducer. The Curie brothers noticed that when pressure is applied to crystals of quartz or Rochelle salt, an electric charge is generated. This charge was directly proportional to the force applied to the crystal; this phenomenon was called "piezoelectricity" from the Greek word for "click". In addition, they demonstrated the inverse piezoelectric effect, which manifested itself when a rapidly changing electric potential was applied to the crystal causing it to vibrate. Current ultrasonic transducers contain piezoelectric crystals that expand and contract to convert electrical and mechanical energy, which is the essence of an ultrasonic transducer. Unfortunately, due to the poor development of electronics at the time, these effects were not fully used.

SUNAR AND OTHER ULTRASOUND PRECURSORS HYDROLOCATOR AND OTHER ALARMS

Fortunately, there was a sonar. All the time that we were in a submerged state, hydroacoustics carefully listened to the sound from the ship's propellers. With complete rest inside the submarine, the sonar could sometimes record the sound of heavy propellers striking from Japanese ships, at a distance of several miles ...

However, it was a double-edged sword, because both submarines and anti-submarine ships used sonar. While the submarine depended in almost everything on listening, anti-submarine ships sent a short burst of energy, called an ultrasonic pulse, which, if it could or could not, would reflect back from the submarine with sufficient “volume” that could be heard ... This technique was known as echolocation and played a key role in the war against submarines.

J. F. CALVERT, SILENT WORK (J. F. CALVERT, SILENT RUNNING)

Sonar predecessors date back to 1838, when Bonnickastl of the University of Virginia, tried to make a map of the ocean floor with sonar. A cartographic survey of the ocean floor was necessary for the placement of telegraph lines and the safe movement of large vessels. This task was previously solved by a slow, cumbersome, and often inaccurate method - using a plumb line. Bonnikastl’s attempts to echo sounder failed, but his research efforts were an incentive to work on this task for other researchers, as soon as the technology matured with the advent of the twentieth century.

At the beginning of the twentieth century, two events occurred that served as catalysts for further research on sonar. On April 15, 1912, after a collision with an iceberg, the Titanic plunged into his ice grave in the North Atlantic. Loud cries of the public caused a wave of interest in the development of a device for detecting underwater objects. In response, an English meteorologist, L.F. Richardson conducted research and registered patents in the field of airborne and ultrasonic underwater detection systems. For unknown reasons, he never completely developed these devices. Therefore, only in April 1914, it became possible to detect an iceberg by using the Fessenden electromagnetic voice coil device. Although this technology was fully accepted, its use has focused on submarine signal transmission and navigation of World War I submarines.

Konstantin Chilovsky, A Russian emigrant living in Switzerland, an electrical engineer, became interested in echolocation due to the death of the Titanic. Later, German submarine attacks on allied vehicles reinforced his interest in sonar development. In 1915, Chilovsky, together with Paul Langevin, an outstanding French physicist, developed a working hydrophone. This pioneering work made a great contribution to the knowledge of generating and receiving supersonic waves, an essential part of the sonar echo principle.

Funding for research in this area was depleted at the end of the First World War, and therefore, research efforts shifted to the field of depth measurement and topographic surveys of the ocean floor. By 1928, using the contribution of Langevin, the French ocean liner Ile de France had a fully functioning device for monitoring the ocean floor and an underwater transmitter for communication between ships. Donald Sproul, a Canadian, conducted research with the first sonar with a range display for the Royal Navy. Although his echo sounder displayed depth to the underlying oceanic rock, Sproul unexpectedly discovered that schools of fish could also be detected with this device.

The search for naval superiority, the brutal actions of submarines and anti-submarine activity in World War II renewed interest in the development of sonar. Formed during the First World War, the Allied Underwater Detection Research Committee became the main component in the development of sonar equipment during the Second World War. During this period, research activities in the areas of hydroacoustic and receiving equipment have boomed, leading to important results in ultrasound technology.

DISCOVERIES IN EVOLUTION OF ULTRASOUND DISCOVERIES

Prior to the development in ultrasonic technology, the integrity of the metal hulls of ships was checked using standard x-rays, this process was time-consuming. Due to the increasing popularity of sonar, it was suggested that it could play a role in assessing the integrity of ship hulls. However, it was necessary to resolve a number of problems. The first obstacle that needed to be overcome was a change in the wavelength of acoustic energy from kilohertz to the megahertz range so that millimeter defects in the metal could be detected. Another problem was that the travel time of the echo pulse should be measured in microseconds rather than milliseconds. In 1941, working independently, Sproul and Firestone were the first to develop technology to overcome these obstacles. At the University of Michigan, Firestone developed a "supersonic reflectoscope," and which was manufactured by Sperry, to detect defects in metal for industrial purposes. Although Sproul and Firestone produced these devices simultaneously in 1941, only after the war ended, in 1946, their results could be published.

In the post-war era, Henry Hughes and Son teamed up with Kelvin, Bottomley and Bayard (industrial rivals before the war) to become Kelvin Hughes a manufacturer of metal flaw detectors. Interestingly, Sproul was forced to resign from this corporation due to his alleged proximity to Russian spies. His replacement was Tom Brown, who, with Ian Donald, played a significant role in the development of the first portable contact ultrasound machine. In addition, Donald and his colleagues conducted research on many of the earliest clinical applications of ultrasound.

BASICS OF ULTRASOUND (ULTRASOUND BASICS)

Assessment of the historical milestones of ultrasound includes knowledge of the methods of transmission and reflection of pulsed waves as well as the modes "A", "B" and "M" of ultrasound.

An example of the early and artless application of ultrasound was the transmission method. This type of ultrasound measured the ultrasonic waves transmitted through the sample to the receiver, which was installed on the opposite side of the sample. The amount of sound transmitted through the tissue and not absorbed by it was recorded. In the method of reflected pulsed waves, the amount of reflected sound was recorded, and both the receiver and transmitter were placed on the same side as the sample.

The amplitude mode or “A” mode of the ultrasound was a one-dimensional image that displayed the amplitude or strength of the wave along the vertical axis and time along the horizontal axis; therefore, the larger the signal returning to the sensor, the higher the “burst”. The brightness or “B” mode, widely used today, is a two-dimensional characteristic of the fabric, so each dot or pixel on the screen represents an individual amplitude burst. Ultrasound “B” mode ties the brightness of the image to the amplitude of the ultrasound wave. Early scanners produced "bistable" images, that is, high-amplitude signals are represented by white dots, and weaker echo signals are displayed on the screen by black dots, without any shades between them. In the gray scale models currently in use, different shades from black to white correspond to amplitudes of different intensities, thereby significantly improving image quality. The “M” mode or the action mode of ultrasound attaches the amplitude of the ultrasonic wave to the display of existing structures, for example, the heart muscle. Since the objects are closer or further away from the sensor, the point corresponding to the border of the fabric moves on the image on the screen. These moving points are then recorded, and their structure is analyzed.

PIONEERS OF MEDICAL ULTRASOUND (PIONEERS OF MEDICAL ULTRASOUND)

Karl Theodore Dussik, a psychiatrist and neuropathologist, began studying ultrasonography in the late 1930s with his brother Frederick, a physicist. In 1937, the Dussiki brothers used a 1.5 MHz transmitter to record changes in the amplitude of energy detected by scanning a human brain. These images, called "hyperphonograms," corresponded to areas of reduced wave transmission (attenuation), it was believed that they were lateral ventricles. Based on the difference in wave transmission between tumor and normal tissue, Dussik suggested that ultrasound could detect brain tumors. Unfortunately, as was later specifically determined by Guttner in 1952, these images made by Dussik were a reflection of the difference in bone thickness. Shortly after it was discovered, the United States Nuclear Energy Committee reported that ultrasound plays no role in the diagnosis of brain tumors; on this basis, funding for medical ultrasound research in the United States has been significantly reduced over the next decade.

Another issue that hindered the investigation of diagnostic ultrasound in medicine was the emphasis on its destructive aspects. During his study of the underwater transmission of supersonic sound waves, Langevin described the destruction of a school of fish and painful sensations after he placed his hand in a tank of water. In 1944, Lynn and Putnam tried to use ultrasound to destroy the brain tissue of experimental animals. Ultrasound caused significant damage to brain tissue and scalp, which led to a wide variety of neurological complications from temporary blindness to death. Later, Fry and Meyer performed craniotomy in order to amputate some parts of the basal nuclei in patients diagnosed with Parkinson's disease. Other similar studies also emphasized tissue destruction, and this quickly led to the abandonment of ultrasound as a neurosurgical instrument.

Ludwig and StruthersWhile working at the Bethesda Naval Medical Research Institute, Maryland, were among the first researchers to report on the use of echo pulse techniques in biological tissue. Unfortunately, since he worked for the military, many of Ludwig’s results were considered limited information and were not published in medical journals. These scientific studies investigated the speed of ultrasonic waves in beef and human limbs, which led to the discovery that the average speed of ultrasound in soft tissue is -1540 m / s. This important achievement has had far-reaching implications for today's ultrasound software. In addition, he demonstrated that ultrasound could show bile stones, which were introduced into the muscles and gall bladders of dogs. These important findings provided the basis for research conducted by two key individuals in the field of ultrasound: John Julian Wilde and Douglas Howry.

Wilde was a surgeon trained in the UK and who immigrated to the United States after World War II. During World War II, Wilde took care of many patients who developed a fatal paralytic ileus, which was secondary to injury from an explosion during a German bombing of London. Having discovered that it is difficult to distinguish between obstruction and ileus, Wilde resorted to ultrasound as a diagnostic tool to differentiate them. He was able to continue his research in this area after immigrating to the United States after taking a position in the laboratory of Owen Wangenstein at the University of Minnesota. Using "A" mode displays and a 15 MHz transducer, Wilde measured the intestinal wall thickness and made visible three different levels of the intestine in a large water reservoir. In 1950, Wilde published his preliminary results on ultrasound determination of intestinal wall thickness and properties of an instance of gastric cancer. Wilde, Neil, and subsequently J.R. Reid noticed that the malignant tissue was more echogenic than the benign tissue. Long before his time, Wilde extrapolated that “there should be the possibility of detecting a tumor of accessible parts of the gastrointestinal tract, both by a change in density and, in all likelihood, by the inability for the tumor tissue to contract and relax.” Although Wilde's early experiments were carried out with scanning in the “A” mode, he made a large and important contribution to the field of ultrasound, some of which led to the development of two-dimensional ultrasonography or “B” mode ultrasonography. With mode B ultrasound, Wilde identified recurrent hip tumor and breast cancer, he published his results in 1952. Unfortunately, because the ultrasound was dependent on who made it and its results were not reproduced sequentially, this data received less recognition than they deserve it.

Wilde's intellectual and financial support for research was minimal due to his unconventional research methods and individual differences with his scientific contemporaries. He rather wanted to find the possibility of immediate clinical application of ultrasound technology than to develop experiments based on theories. Despite these difficulties, Wilde was able to develop a scanning device that was used to scan breast cancer patients and also developed transrectal and transvaginal sensors. With this device, he imaged a brain tumor in a pathology sample and localized a brain tumor in a patient after craniotomy.

Douglas Howry, another pioneer of the 1940s, played an important role in the development of ultrasound and ultrasonic devices. Howrie, unlike Wilde, focused more on the development of equipment and the applied theory of ultrasound than its clinical application. Although his initial work led to the creation of an ultrasound machine that produced insufficiently optimal images, Howry's final goal was to make a more sophisticated device that would be "somewhat comparable to the actually large number of sections of structures made in the pathology laboratory."

Howry became interested in studying ultrasound during his internship in radiology at the University of Denver Hospital in 1948. He interrupted his internship and began private practice so that he could devote more time to developing diagnostic ultrasound equipment. Working with W. Roderick Bliss, an electrical engineer, Howry began designing the first B-mode scanner in 1949. Unlike Wilde, Howry was interested in both the behavior of ultrasonic waves in tissue and the design of a functional ultrasound machine. Howry's work was modeled after classical research because he applied the theory of acoustics, physiology, and development in the laboratory before testing him in the clinic. After he successfully developed an ultrasonic machine that yielded consistently accurate and reproducible results, he initialized the study in human objects.

In 1951, Howry met Joseph Holmes, Nephrologist at Veterans Administrative Hospital (AB) in Denver. Holmes played a leading role in obtaining institutional support, which enabled Howrie to continue his research on AV Denver equipment. Working on redundant airborne radar equipment, Howry and Bliss, together with Gerald Posakoni (another engineer), developed the first linear contact scanner. This scanner used a cattle watering container as an immersion bath to help connect the sensor to the patient being examined. The sensor was mounted on a wooden bus and moved past the patient to obtain an image.

Secondary mappings have been eliminated. Although the scanner produced images of acceptable quality, it required that the patient remain immersed and motionless for long periods, and therefore was considered impractical for use in a clinical setting.

In the late 1950s, Howry and colleagues developed an ultrasound scanner with a semicircular cell with a plastic window. The patient was fastened with a belt to the plastic window and, although he was not immersed in water, the patient still had to remain motionless for a long time (Fig. 2) (No picture). In the early 1960s, W. Wright and E. Miers joined the Howry research group to concentrate on this inherent problem with a water thermostat connection system. The result of this group effort was the production of a direct contact scanner. In 1961 Myers and Wright teamed up to form Physionics Engineering, and within a year produced the prototype of the first portable contact scanner in the United States. This scanner had a hinged manipulator with positioning mechanisms in each connection, to combine the information received from the sensor.

Howry Crawler Scanner. The patient sat in a modified dental chair and was fixed in front of the plastic window of a semicircular cuvette filled with salt. (From Goldberg B., Gramik R, Freimanis A.K: Early history of ultrasound in diagnostics: the role of American radiologists. Am. J. Roentgenol 160: 189-194, 1993; with permission).

During this same time, Jan Donald led the study of ultrasound in England. Donald was an outstanding Royal Air Force veteran in World War II who became acquainted with sonar and radar equipment during military service. In 1955, as a member of the State of Obstetrics and Gynecology at the University of Glasgow, Donald borrowed a metal flaw detector from a local manufacturer and used it to examine pathological specimens. With this "A" mode ultrasound machine, Donald was able to differentiate different types of tissue in newly excised fibroids and ovarian cysts. From this humble beginning, he and another gynecologist, John McVicar, along with Tom Brown, an engineer from the Calvin and Hughes Science Tool Company, developed the first contact composite scanner.

In June 1958, Donald published an article entitled “Investigation of Abdominal Masses by Pulse Ultrasound,” which was a milestone in ultrasound. This work describes a case in which the use of ultrasound dramatically changed the treatment of a 64-year-old woman who had abdominal pain, weight loss, and who was supposed to have ascites. After conducting routine tests, she was diagnosed with advanced gastric cancer, but Donald diagnosed a cyst mass with ultrasound, which was later successfully resected and found to be a benign mucous ovarian cyst.

Donald and his partners in Glasgow have done a huge amount of research in the field of ultrasound, especially in the field of obstetrics and gynecology. He accidentally discovered that a full bladder provided a natural acoustic window for the transmission of ultrasound waves through the renal pelvis, which made it possible to display the pelvic structures more clearly. Using this technique, Donald made visible small pelvic tumors, an ectopic pregnancy, and the location of the placenta. Donald was the first to measure the biparietal diameter of the fetal head and use it as a fetal growth index. His contribution was well received in the medical field, and he essentially endorsed the concept that ultrasound would play a major role in medical diagnostic imaging.

FURTHER ACHIEVEMENTS (FURTHER DEVELOPMENTS)

The 1950s were an important time for ultrasound. Many of the advances in ultrasound technology that have taken place during that decade have found new applications in the 1960s and 1970s. In 1955 Jaffe discovered the piezoelectric properties of polarized solid solutions of lead, zirconate, titanate. This important discovery ultimately led to smaller and improved ultrasonic sensors. Turner from London, Lexell from Sweden, and Kazner from Germany used these advanced devices to perform midline encephalography to detect epidural hematomas in patients with traumatic brain injuries. Midline encephalography remained the standard diagnostic technique for evaluating traumatic brain injury patients until the 1970s when CT (computed tomography) was introduced.

Inge Edler  from Sweden and Karl Hellmouth Hertz  were the main pioneers in the field of echocardiography. In the early 1950s, Edler, a cardiologist, suggested that ultrasound might play a role in evaluating the heart. Hertz borrowed a metal flaw detector from a shipyard, applied a probe to his chest, and observed mappings that varied in amplitude and range in accordance with his heart rate. Subsequent studies of Hertz and Asberg led in 1967. to the first two-dimensional operational, machine that displays the heart. Around the same time, the first recordings of the simultaneous "M" mode and the intracardiac Doppler blood flow were discovered by Edler and Lindstrom.

In the 1960s, the limitation of ultrasound technology was the slow and tedious collection of images and the extreme image resolution caused by patient movement. Despite these constraints, ultrasound earned the respect of the medical community and quickly became a routine imaging method. Over the next two decades, improvements in ultrasound technology have accelerated, and its use in many medical specialties has become standard. As he said in 1976. Ian Donald: "The medical sonar has quite suddenly grown and reached adulthood; in fact, its surge in growth over the past few years has been almost an explosion."

ADVANCES IN REAL-TIME AND GRAY-SCALE IMAGING IMPROVEMENTS AND OPERATIONAL DISPLAY AND DISPLAY

Early imaging systems consisted of conventional cathode-ray oscilloscopes that were exposed with photographic shutters open to capture the image on the screen. Due to the delay inherent in these systems, many weaker mappings were recorded, but they were not as intense as mappings from the section of surfaces. These displays from the dimmer, produced an early "grayscale" image, which determined the density of the fabric and produced an image with better resolution.

Later models used a “bistable” memory oscilloscope, which simplified the scanning process and eliminated the need for shutter photography. With the elimination of images from the camera with the shutter, “gray” or less intense images were lost, resulting in worse images. Required for the development of a television scanning converter tube and with the support of George Kossoff from Australia, grayscale was again in demand. Further improvements in the field of electronics, such as, for example, analog and digital scanning converters, even led to the best ultrasound images. Digital scanners, launched in 1976, produced stable, reproducible, and very clear images.

A significant turning point in the development of ultrasound was an automatically renewed sonographic image, or operational display. This scanning technique allows you to select and display images so quickly that their formation and display seems simultaneous. Live imaging was initiated in the mid-1950s by JJ Wilde, but this breakthrough has been ignored for more than ten years due to the improved images produced by the Howry ultrasound machine. The first commercially available operational ultrasound machine was the Vidoson machine (Siemens Mecical Systems, Iselin, NJ). This machine had a rotating sensor in a water tank and was first used by Hoffman in 1966. and Hollander in 1968, in order to outline the structures in the female renal pelvis. Vidoson produced 15 images per second, creating a relatively flicker-free cinematic representation of the organ being displayed. With operational imaging, the examining specialist received immediate feedback, which was the most important means of creating an ultrasound, imaging that is not so dependent on the operator.

MODERN APPLICATIONS (RECENT APPLICATION)

The development of Vidoson required other technologically advanced solutions, such as, for example, linear sensors and phasing sensors of arrays. During the 1970s and 1980s, numerous improvements and modifications to these sensors and ultrasound machines served to improve ultrasound images and expanded the use of this technology. In general surgery, ultrasound has undoubtedly played a role in the diagnosis of breast, biliary tract, pancreatitis, and thyroid disease. The first initiators in these areas were Leopold and Doust, Kobayashi, Wagai, Colu-Beglet, Stuber and Mishkin. Friday popularized the use of ultrasound to localize abdominal abscesses, and Goldberg in 1970. suggested using it for early detection of ascites. Although corrective radiology has become very complex, its beginnings date back to 1969, when Kratochville proposed the use of Mode A ultrasound for percutaneous drainage procedures. Goldberg and Pollack came out in favor of using B-mode ultrasound in 1972.

Other areas of general surgery, especially injuries, relied on portability of ultrasound and speed, access to patients in situations on which life or death depends. In 1971, Christensen from Germany first reported using ultrasound to evaluate a patient with a blunt object injury. This was followed by a prospective study by Asher who studied the use of ultrasound as a control technique for suspected spleen rupture. Tyling of the University of Cologne, investigated the use of ultra-sonography to evaluate thorax, retroperitoneal space, and other intra-abdominal organs in the mid-1980s. Although most of the early research was done in Europe and Asia, surgeons have recently become more popular with ultrasound in North America.

Over the past decade, progress in ultrasound equipment has made it a stronghold for evaluating patients with vascular pathology. ultrasound serves as a control tool in assessing cerebrovascular disease and abdominal aortic aneurysms, as well as for evaluating patients for deep venous thrombosis and peripheral vascular disease. These studies rely heavily on the theory proposed more than a hundred years ago by Christian Andreas Doppler.

CHRISTIAN DOPPLER AND THE DOPPLER EFFECT

It is especially necessary to mention Christian Andreas Doppler, an Austrian mathematician and physicist, who in 1841. made his speech: "On the colorimetric characteristics of the radiation of double stars and some other stars of the sky" for an audience of only five people and a stenographer. In his treatise, Doppler suggested that the observed color of the star is caused by the spectral shift of white light and this is due to the motion of the star relative to the earth. To substantiate his theory, Doppler used an analogy based on the transmission of light and sound. Although his theory with respect to light was erroneous, Doppler theories about changing the frequency of sound waves were correct. The Doppler effect, as a theory has become known, is defined as "observed changes in the frequency of transmitted waves when there is relative movement between the wave source and the observer." This theory has been applied to many scientific aspects, including astronomy and medicine.

The first application of the Doppler effect in medicine included measuring the difference in travel time between two ultrasonic wave sensors that move upstream and downstream through the current blood. Studies on the clinical use of the Doppler principle were carried out simultaneously throughout the global scientific family. The initial application of this principle relates to the work of Kalmus, who completed his electronic flowmeter in 1954. Shigeo Satomura, a physicist at the University of Osaka, also pioneered the use of the Doppler principle in ultrasound. In 1956, Satomura published its data on Doppler signals, reports that were generated by the movement of the heart valve. Additional work was carried out on the study of normal and abnormal valve movement, it was an atraumatic method for diagnosing valve disease. Unfortunately, Satomura's important work was unrecognized in the United States, in large part because of the difficulties that Western scholars encountered in reading Japanese literature. Often, ultrasounds performed in Japan were several years ahead of Western studies and duplicated independently in the United States and elsewhere. Satomura applied the Doppler principle to ultrasonic energy for several years before he published his findings on the ultrasonic rheograph used to measure blood flow. However, only in the following year, the Doppler treatise: “On the colorimetric characteristics of the radiation of binary stars and some other stars of the sky” 1842. (From Mawlik D: Doppler ultrasound in obstetrics and gynecology. New York, Springer, 1997; with permission.)

Franklin, Schlegel, and Rushmer  University of Washington published their work on a flowmeter that was used to record blood flow through an intact vessel in dogs.

Although early imaging with Doppler ultrasound was useful, he used continuous wave emission, which impeded the ability to distinguish between moving structures within the range of his beam. The pulsed Doppler radar is designed for the strobe-amplitude method, making it possible for the device to distinguish between several moving targets. A group from Seattle, consisting of Baker, Watkins, and Reid, began working on the Doppler pulsating wave in 1966; they were among those first who made such a device by 1970. Throughout that decade, the Seattle group continued to make improvements, and eventually they connected an operational mechanical rocker scanner to the pulsating Doppler machine. The mechanical sensor played a dual role: in both live imaging and Doppler functions. These instruments became very popular in the 1980s as imaging instruments for assessing carotid artery disease. Additional progress in the microprocessors of these machines, was a harbinger of the following changes, which was the display of color Doppler flow. This new technology has improved the ability of the equipment to detect plaque and blood clot and quantify the hemodynamic significance of carotid lesions.

Among the pioneers in the field of Doppler ultrasound were Callaghanwho performed early experiments with ultrasound evaluation of fetal heart movements and Strandness, which published its results on the use of the Doppler effect, to evaluate patients with peripheral vascular disease.

Current directions in Doppler / duplex mapping include the "power of the Doppler effect" proposed by Fuchsin. The "power of the Doppler effect" has expanded the sensitivity to blood flow, which allows an improved display of slowly flowing structures. Ultrasonic contrast agents expand the acoustics of the blood flow, making it more visible to Doppler. These ultrasonic “amplifiers” can facilitate the ability to detect tumors, make visible ischemic regions, and perform ultrasound angiography.

Three-dimensional ultrasound image of a 26-week embryo. (courtesy of ALOKA, Wallingford, CT.)

SUMMARY (SUMMARY)

Ultrasound in medical diagnostics may have a brief history, but its roots go back to the beginning of the nineteenth century. From its modest beginning in military institutions where ultrasound was used to study pathological specimens, to the routine assessment of the fetus, patients with wounds and cerebrovascular disease, ultrasound has secured its position as a key diagnostic technique, as it is now. so in the future. His ability to diagnose heart valve disease and congenital heart disease has reduced the need for invasive cardiac angiography with associated risks. In addition, ultrasound expanded the medical diagnostic tools and made it possible to “look inside” of its patients in the enodoluminal, transvaginal, transrectal, and transesophageal areas.

Despite all these successes, the scientific study of ultrasound is still encouraged, and today's ideas will be technology tomorrow.

References

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  The existence of ultrasonic vibrations in nature that are beyond the ears of the human ear has been known for a long time, these vibrations are called ultrasonic waves. The discovery of these waves is connected with the name of the Italian scientist Lazzaro Spalanzani, who suggested that the ability of bats to fly in the dark and not run into obstacles depends not on vision, but on sound vibrations that a person is not able to hear. After 250 years, Galambos (1942) and Grifin (1944) confirmed this brilliant idea.

The progress of using the nature of ultrasound was made by the discoveries of Galtona (1880), brothers Pierrl and Jagne, Curie, who described the piezoelectric phenomenon - the appearance of a free charge on the surface of some crystals during their mechanical deformation. This discovery was theoretically substantiated a year later by Lipman, who discovered that when an electric charge acts on the surface of a crystal, it deforms. These discoveries laid the foundation for the creation of devices that generate high-frequency ultrasonic waves. For many years, these discoveries received little attention. Interest has increased in connection with the use of ultrasound in medicine.

In 1940, George Ludwig, Douglas Howry, and John Wild, independently of each other, showed that ultrasound signals sent to the body return back to the same sensor, reflected from the surfaces of structures of different densities.

Although ultrasound has been used in medicine not so long ago, by now it has been successfully used in a number of its fields for therapeutic and diagnostic purposes. Initially, ultrasound was mainly used in therapy due to mechanical influences causing displacement of ultrasound pressure in the tissues, and the thermal effect that occurs inside the tissues, leading to physicochemical actions. Ultrasound therapy has been found to be especially effective in certain pathological conditions (ankylosing spondylitis, neuralgia, neuritis, joint inflammation and other inflammatory processes).

It turned out that, along with a positive effect, its use is absolutely contraindicated in the treatment of parenchymal organs (liver, spleen, kidneys, lungs, heart, brain, thyroid gland, etc.).

The dosed use of ultrasound in therapy is due to two reasons:

The ultrasound field penetrates the tissue in the treatment of heterogeneous,

The inhomogeneity of the ultrasonic field is still increasing due to the heterogeneity of unirradiated tissues.

The difference in tissue separated by fascia, septum, is the cause of numerous inhomogeneous reflections, affecting the effectiveness of the ultrasonic field. These features of the ultrasound field and tissues should be taken into account when choosing the intensity and time of exposure to ultrasound to obtain the maximum therapeutic effect. The upper limit of the therapeutic dose intensity is 3 W / cm2.

The great merit of using ultrasound in therapy belongs to Pohlmann (1939, 1951). He also studied the biological effects of medium and high intensity ultrasound. The primary use of ultrasound for therapeutic purposes is associated with the use of relatively simple ultrasound generators in the production of therapeutic ultrasound equipment.

  The first attempts to use ultrasound for diagnostic purposes are connected with the name of the Vienna neuropathologist Karl Dussik (1937, 1941, 1948), who, using two sensors located one against the other in the head region, managed to locate a brain tumor. Despite some successes, due to the complexity of the interpretation of the results, the method was criticized and forgotten for some time. In 1946, Denier tried to obtain images of the heart, liver and spleen using ultrasound. Keidl (1950), using an ultrasound probe with a frequency of 60 KHz, determined the volume of the heart muscle by measuring the absorption of ultrasound in the heart muscle and lung tissue, but the results were inconclusive.

The stage of serious introduction of ultrasound in diagnostics begins with the development of a pulsed echo method and obtaining a one-dimensional image (A-method). Although the first reports of the possibility of obtaining a one-dimensional ultrasound image appeared in 1940 (Gohr and Vederkind), in practice, the method began to be applied only 10 years later, when Ludwig and Strutners managed to identify gallstones and a foreign body sewn into the dog’s muscle tissue. They suggested that tumors could also be detected with this method. Wild and Reid (1952), examining the mammary glands, found that tumor tissue reflects more than healthy tissue, thereby proving the effectiveness of the method for diagnostic purposes.

These encouraging data on the effectiveness of the method have contributed to its widespread adoption in various fields of clinical medicine. The Swedish scientists Edler and C. Hertz (1954) are the founders of echocardiography, although for a long time the method did not find clinical application due to imperfections in the equipment and erroneous interpretation of the recorded heart structures. Publications by German scientists S.Tffert et al. (1959) on the successful diagnosis of atrial tumors, then by American scientists G. Joyner (1963), R. Gramiak (1969) and many others showed that information on a healthy and sick heart obtained by bloodless , does not cause harm and anxiety to patients.

Photo: likesuccess.com

Leksell (1955) developed the basics of echoencephalography and was the first to succeed in locating the brain hematoma with the help of displacement of the median echo. This technique was further developed by S. Lepsson (1961), C. Grossman (1966), W. Schifer et al. (1968) and others. The one-dimensional ultrasound method in ophthalmology was first used in 1956 by Mundt and Hughes, and a year later by Oksala and Lehting. The beginning of the introduction of this method in obstetric and gynecological practice is associated with the names of Scottish researchers I. Donald, J. Mac Vicar and E. Brown (1961). The first measurements of the fetal head by the ultrasound method were carried out by I. Donald. They laid the foundation for the application of the two-dimensional method (B-method) in obstetrics and gynecology. The development of a two-dimensional method for obtaining images was a major achievement in the development and improvement of ultrasound equipment.

An echocardiogram of the heart, the atria and ventricles are visible in the image. Photo: Wikipedia.org.rf

For the first time in a clinical setting, one method was independently used by Howry and Bills, Wild and Reid (1955-1956). The possibilities of using ultrasound for diagnostic purposes in gastroenterology are given by G. Baum and I. Greenwood (1958) when they described the two-dimensional method (B-method).

Further improvement of ultrasound diagnostic devices is associated with the work of Kossoff and Garrett (1972, Australia), which received a grayscale image. Then they improved real-time instruments. In 1942

Christian Doppler described the propagation of waves from a moving source of oscillations and the influence of other relative movements on their frequency. This Doppler effect was applied in acoustics, and later on it began to produce devices capable of detecting heart movement.

The roots of the development of ultrasound as a diagnostic method of research in obstetrics and gynecology go back to those times when the distance under water was measured using ultrasonic (ultrasound) waves. A high-frequency signal not heard by the human ear was generated by the English scientist F. Galton in 1876.

Joseph Woo, MD Royal College of Obstetricians and Gynaecologists, RCOG, London, UK; College of Obstetrics and Gynecology, Hong Kong Academy of Medicine, HKAM, China

The origins
  A breakthrough in the development of ultrasound technologies was the discovery by the brothers P. and J. Curie of the piezoelectric effect (France, 1880). The first working sonar sonar system SOUND Navigation And Ranging (SONAR) was designed in the USA in 1914.
  The progenitor of medical ultrasound was the RAdio Detection And Ranging (RADAR) system, invented in 1935 by the British physicist R. Watson-Watt. Such radar systems were direct predecessors of subsequent two-dimensional sonar and medical ultrasound systems, which appeared in the late 40s of the XX century.
  Another area that preceded the development of ultrasound in medicine was the development of pulsed ultrasonic metal flaw detectors, which were used to verify the integrity of the metal hulls of ships, tanks, and other equipment, which began in the 1930s. The concept of detection of metal defects was developed by the Soviet scientist S.Ya. Sokolov in 1928, and the design of the first ultrasonic detectors and their subsequent improvement began in the 40s in the United States, Great Britain, Germany, France, Japan and in several other countries (Fig. 1).

  Ultrasound in medicine
For the first time in medicine, ultrasound began to be used as a treatment method in the late 1920s and early 1930s.
  In the 40s, ultrasound was used to relieve pain in arthritis, gastric ulcer, in the treatment of eczema, asthma, thyrotoxicosis, hemorrhoids, urinary incontinence, elephantiasis and even angina pectoris (Fig. 2).
  The use of ultrasound as a diagnostic method for the detection of tumors, exudates and abscesses in 1940 was first proposed by German clinicians H. Gohr and T. Wedekind. In their opinion, such a diagnosis could be based on the reflection of an ultrasound wave from pathological volumetric formations of the brain (the principle of the metal flaw detector). However, they were not able to publish convincing results of their experiments, and therefore their studies were not popular.
  In 1950, American neurosurgeons W. Fry and R. Meyers used ultrasound to destroy the basal ganglia in patients with Parkinson's disease. Ultrasound energy has been successfully used in therapy and in rehabilitation medicine. So, J. Gersten (1953) used ultrasound to treat patients with rheumatoid arthritis.
  A number of other clinicians (P. Wells, D. Gordon, UK; M. Arslan, Italy) used ultrasound energy to treat Meniere's disease.
  The founder of diagnostic ultrasound is considered to be an Austrian neurologist, psychiatrist K.T. Dussik, who first applied ultrasound for diagnostic purposes. He determined the location of brain tumors by measuring the intensity of the passage of the ultrasound wave through the skull (Fig. 3). In 1947, K.T. Dussik presented the research results and called his method hyperphonography.
  However, later the German clinician W. Guttner et al. (1952) the pathology in such ultrasound images was regarded as artifacts, since K.T. Dussik took the attenuation of ultrasound wave reflections from the bones of the skull for pathological formations.
G. Ludwig (USA, 1946) conducted experiments on animals to detect foreign bodies (in particular calculi in the gallbladder) using ultrasound waves (Fig. 4). Three years later, the results of his research were officially made public. At the same time, the author noted that the reflection of ultrasonic waves from soft tissues interferes with a reliable interpretation of the results obtained from such ultrasound. However, despite this, the studies of G. Ludwig made a certain contribution to the development of ultrasound in medicine, during which the scientist made a number of important discoveries. In particular, he determined that the range of transmission speed of ultrasound in the soft tissues of animals is 1490-1610 m / s (an average of 1540 m / s). This value of the ultrasonic wave is still used in medicine today. The optimal frequency of ultrasound, according to the researcher, is 1-2.5 MHz.
  English surgeon J.J. Wild in 1950 began a study of the possibility of using ultrasound for the diagnosis of surgical pathology - intestinal obstruction. While working in the United States together with engineer D. Neal, he discovered that malignant tumors of the stomach have a higher echogenic density compared to healthy tissue.
  A year later, the American radiologist D. Howry, together with colleagues (director of the medical research laboratory J. Homles and engineers W.R. Bliss, G.J. Posakony) developed an ultrasound scanner with a semicircular cell with a window. The patient was fastened with a belt to the plastic window, and he had to remain motionless for a long time of the study. The device was called a somoscope, scanned the organs of the abdominal cavity, and the results were called somagrams.
  Soon, the same researchers (1957) developed a cuvette scanner. The patient sat in a modified dental chair and was fixed in front of the plastic window of a semicircular cell filled with saline (Fig. 5).
  In 1952, the American Institute of Ultrasound in Medicine (AIUM) was founded in the United States.
  Some time later, in 1962, J. Homles, together with the engineers, designed a lever scanner that could already move over the patient with manual operator control (Fig. 6).
  In 1963, the first hand-operated contact scanner was developed in the United States. This was the beginning of the formation of the most popular static ultrasound devices in medicine (Fig. 7).
  Since 1966, AIUM began accrediting ultrasound practice. To obtain a license for such practice in obstetrics and gynecology, the doctor had to interpret at least 170 ultrasound images per year.
In 1966, the first World Congress of Ultrasound Diagnostics in Medicine was held in Vienna, the second - in Rotterdam in 1972. In 1977, the British Medical Ultrasound Society (BMUS) was founded.
  Thus, since the end of the 50s of the last century, studies have begun in various countries — the USA, Germany, Great Britain, Australia, Sweden, and Japan — on the possibility of using ultrasound to diagnose diseases. The principles of sonar (A-mode of ultrasonic waves) and radar (B-mode) were used as the basis for their implementation.

  Ultrasound diagnostics in the USSR
  Research on the use of ultrasound in medicine was also carried out in the USSR. In 1954, on the basis of the Acoustic Institute of the Academy of Sciences of the USSR, an ultrasound department was created under the guidance of Professor L. Rosenberg. The first mention of the use of ultrasound in therapy dates back to the 1960s.
  The Research Institute of Medical Instruments and Equipment of the USSR produced experimental ultrasonic devices Ekho-11, Ekho-12, Ekho-21, UZD-4 (1960); UZD-5 (1964); UTP-1, UDA-724, UDA-871 and Obzor-100 (early 70s). These models were intended for use in ophthalmology, neurology, cardiology and in a number of other areas of medicine, however, according to the order of the government, they were not introduced into practical medicine. And only from the end of the 80s, ultrasound testing began to gradually be introduced into Soviet medicine.

  Ultrasound in Obstetrics and Gynecology
  The use of ultrasound in obstetrics and gynecology begins in 1966, when there is an active establishment and development of centers for the use of ultrasound in various fields of medicine in the United States, Europe and Japan.
  The pioneer in the field of gynecological ultrasound examination was the Austrian doctor A. Kratochwil. In 1972, he successfully demonstrated the ability to visualize ovarian follicles using ultrasound (Fig. 8) and soon became the most famous ultrasound diagnostician of the time.

  Transvaginal scanning
  In 1955, J.J. Wild (UK) and J.M. Reid (USA) used the A-mode for transvaginal and transrectal ultrasound scanning. In the early 60s, A. Kratochwil presented his study of fetal heart rate at the 6th week of gestation using a transvaginal sensor (Fig. 9). At the same time, this ultrasound method was introduced by L. von Micsky in New York.
  In Japan in 1963, S. Mizuno, H. Takeuchi, K. Nakano et al. proposed a new version of the A-mode transvaginal scanner. The first pregnancy scan with its help was carried out at 6 weeks gestation.
In 1967, in Germany, Siemens developed the first ultrasound scanner that uses the B-mode to diagnose abdominal and pelvic pathology, which has been successfully used in gynecology.
  Already in the early 70s, ultrasound in gynecology was used to diagnose solid, abdominal and mixed formations of another various pathology of the pelvic organs. So, German researchers B.-J. Hackelöer and M. Hansmann successfully diagnosed quantitative and qualitative changes in the follicles during the ovarian cycle using B-mode. The condition for a successful pelvic ultrasound was a complete bladder.
  The opportunity for sonography of the fetus marked a new stage in the development of obstetrics and prenatal diagnosis.
  Australian clinicians G. Kossoff and W. Garrett in 1959 introduced the CAL contact water echoscope (Fig. 10), with which it was possible to study the fetal chest. This ultrasound machine was used to identify fetal malformations.
  In 1968, Garrett, Robinson, and Kossoff were among the first to publish the work “Fetal Anatomy Imaged by Ultrasound,” and two years later they presented their first work on ultrasound diagnosis of fetal malformations, which described polycystic kidney disease detected in the fetus at 31 week of gestation (Fig. 11).
  In 1969, a gray scale CAL echoscope was released.
  In 1975, a water scanner with a highly sensitive sensor, the UI Octoson, was designed (Fig. 12).
  In the early 60s, when conducting obstetric ultrasound (Europe, USA, Japan, China, Australia), the A-mode was used, with which the signs of pregnancy were determined (fetal heart rate was measured), the location of the placenta, and cephalometry was performed. In 1961, I. Donald (Great Britain) proposed measuring the biparietal diameter (BPD) of the fetal head (Fig. 13). In the same year he described a case of hydrocephalus in a fetus.

  B-mode
  In 1963, I. Donald and MacVicar (Great Britain) for the first time described the image of the membranes obtained using the B-mode ultrasound. By measuring the diameters of the membranes L.M. Hellman and M. Kobayashi (Japan) in 1969 determined signs of full-term fetus, and P. Joupilla (Finland), S. Levi (Belgium), and E. Reinold (Austria) in 1971 determined the relationship with early pregnancy complications. In 1969, Kobayashi described ultrasound signs of an ectopic pregnancy using the B-mode ultrasound.
Despite the fact that a number of obstetrician-gynecologists determined the cardiac activity of the fetus using the A-mode (Kratochwil in 1967 using a vaginal A-scan for a period of 7 weeks; Bang and Holm in 1968 using A- and M-modes on 10 weeks), the practical use of ultrasound in obstetrics to determine the fetal cardiac activity began in 1972, when H. Robinson (Great Britain) presented the results of his fetal ultrasound scan at a gestational age of 7 weeks.
  B-mode placentography was successfully described in 1966 by the Denver group of researchers (USA) (Fig. 14).
  In 1965, the American scientist H. Thompson described a method for measuring thoracic circumference (TC) as a method for determining fetal growth (Fig. 15). Moreover, the error of its measurements was about 3 cm in 90% of the total number of studies. H. Thompson also developed a method for determining fetal body weight by BPD and TS, the error of which was about 300 g in 52% of children.
  One of the most famous researchers on ultrasound in obstetrics is the English professor S. Campbell. In 1968 he published the work “Improvement of ultrasound methods of fetal cephalometry”, where he described the use of A- and B-modes for measuring the BPD of the fetal head. This work became the standard for practical ultrasound in obstetrics in the next 10 years.
  In 1972, using a B-mode ultrasound, the scientist diagnosed fetal anencephaly for a period of 17 weeks, and in 1975, spina bifida. These were the first pathologies correctly identified using ultrasound, which were an indication for abortion. In 1975, S. Campbell et al. They suggested measuring abdominal circumference (AC) in order to determine body weight and the degree of development of the fetus (Fig. 16).
  Clinicians M. Mantoni and J. Pederson (Denmark) were the first to describe the possibility of visualizing the yolk sac using B-mode; E. Sauerbrei and P. Cooperberg (Canada) visualized the yolk sac using ultrasound; German researchers M. Hansmann and J. Hobbins were among the first to study fetal malformations using ultrasound.
An innovation that fundamentally changed the development of practical ultrasonic testing was the invention of real-time scanners. The first such device, called Vidoson, was developed by German researchers W. Krause and R. Soldner (together with J. Paetzold and O. Kresse). It was released in 1965 in Germany by Siemens Medical Systems and took 15 shots per second, which made it possible to record fetal movements (Fig. 17). In 1968, with the help of this scanner, German clinicians D. Holander and H. Holander diagnosed 9 cases of fetal edema.
  In 1977, C. Kretz (Austria) developed the Combison 100 ultrasound machine (Fig. 18), which KretzTechnik began to produce. It was a circular rotary scanner operating in real time and designed for ultrasound of the abdominal cavity and other parts of the body.
  The American clinician J. Hobbins in 1979, using a real-time scanner, measured the length of the fetal thigh. Based on this, G. O’Brien and J. Queenan (USA) in the same year were able to determine the presence of such a pathology of fetal development as skeletal dysplasia. Doctor of medicine P. Jeanty (USA) in 1984 compiled a table of all sizes of fetal bones during development.
  In the early 80s, a static scanner was designed to quickly take high-resolution images.
  At that time, there were about 45 large and small enterprises producing ultrasound equipment in the world.
  It should be noted that in the late 70s - early 80s, small portable ultrasound scanners (mini-scanners, etc.) were created, which are portable devices that could be used for diagnosis directly at the patient's bedside, including at home (Fig. 19).
  Doppler ultrasound
  As you know, the essence of the Doppler effect is to change the frequency of the waves when reflected from a moving object. This phenomenon was first described more than 100 years ago by the Austrian mathematician and physicist C. Doppler (1842). Ultrasound Doppler as a diagnostic diagnostic method in medicine was introduced in 1955 by Japanese scientists S. Satomura and Y. Nimura, who studied with it the work of heart valves and pulsation of peripheral vessels. Seven years later, their compatriots Z. Kaneko and K. Kato found that using the ultrasound Doppler method, you can determine the direction of blood flow.
  The study of the Doppler effect in the 60s was also conducted in the USA, Great Britain and other countries.
In practical obstetrics and gynecology, the Doppler effect began to be used somewhat later. In 1964 in the USA D.A. Callagan first applied this diagnostic method to determine pulsation of fetal arteries. A year later, the American gynecologist W. Johnson, using the Doppler effect with 100 percent accuracy, determined the age of embryonic development in 25 fetuses (12 weeks). A year later, E. Bishop using Doppler ultrasound in the third trimester of pregnancy established the place of attachment of the placenta in 65% of the women examined by him. In the same year D.A. Callagan et al. described fetal heartbeat by cardiac Doppler signals.
  In 1968, the Japanese H. Takemura and Y. Ashitaka described the nature and speed of blood flow in the umbilical artery and vein, as well as placental blood flow (Fig. 20).
  P. Jouppila and P. Kirkinen (Finland) in 1981 revealed a relationship between a decrease in the blood flow velocity in the umbilical vein and a slowdown in fetal growth. In 1983, S. Campbell revealed the diagnostic value of uterine and placental blood flow in the diagnosis of preeclampsia.
  The subsequent development of Doppler ultrasound was associated with color scanning. M. Brandestini et al. (USA) in 1975 developed a 128-point multi-pulse Doppler system, where the speed and direction of blood flow were shown in color (Fig. 21).
  The French clinician L. Pourcelot in 1977 was also among the first to describe color Doppler ultrasound. However, the active development of Doppler ultrasound as a diagnostic method in medicine began in the 80s with the advent of new, more advanced technologies.
  The introduction of Doppler ultrasound into gynecological practice began in the mid-80s, when K. Taylor (USA) described blood flow in the ovarian and uterine arteries, and A. Kurjak (Yugoslavia) used transvaginal color Doppler in the diagnosis of pelvic blood flow.
  The development of two-dimensional and color Doppler ultrasound was almost simultaneous and occurred in the late 80s. At the beginning of 1990, A. Fleischer (USA) was one of the first to describe the vascularization of ovarian cancer using color transvaginal doppler.
  Improving the quality of ultrasound continued for 80-90 years due to the development of microprocessor technology (Fig. 22). At this time, ultrasound began to be actively used in various fields of medicine, including in obstetrics and gynecology. According to statistics from the FDA (Food and Drug Administration), in the United States from 1976 to 1982, the frequency of use of ultrasound in medical institutions increased from 35 to 97%.
Thus, in 1975, before the development of real-time scanners, in the United States there were five indications for ultrasound in obstetrics: measuring BPD, determining the volume of amniotic fluid, diagnosing early pregnancy complications, gestational timing and position of the placenta. Since the 80s, the list of such evidence has expanded greatly. So, standards were developed for determining the fetal age and development of the fetus according to the results of ultrasound by determining the following parameters: the length of the sacrum-crown (CRL), head circumference (NA), thigh length (FL), BPD, AS. A number of other parameters were determined in cases of impaired fetal development.
  In subsequent years, normograms were developed to assess the growth and development of the fetus according to the following parameters: binocular diameter (K. Mayden, P. Jeanty et al., 1982), hip circumference (Deter et al., 1983), clavicle length (Yarkoni et al ., 1985) and feet (B. Mercer et al., 1987), according to the fractional size of the spine (D. Li et al., 1986) and the auricle (JC Birnholz et al., 1988).
  With the invention of real-time ultrasound scanners, many fetal malformations were diagnosed. However, the resolving possibility of ultrasound machines of that time made it possible to visualize this pathology only in late pregnancy. In 1981, Stephenson published a review describing about 90 different fetal malformations that can be detected by ultrasound. Anomalies of development directly diagnosed by ultrasound in those days included anencephaly, hydrocephalus, umbilical cord hernia, duodenal atresia, polycystic kidney disease, fetal edema, limb dysplasia. Difficulties for ultrasound scanning were the facial area of \u200b\u200bthe fetus, limbs and heart. With the advent of higher resolution scanners and transvaginal sensors, the diagnosis of fetal development pathology was simplified, and defects could already be identified not in the third trimester of pregnancy, but in the second and first.
  It has also become possible to determine the fetal movements and fetal breathing movements (FBM). FBM scanning was first proposed by researchers G. Dawes and K. Boddy (Great Britain) in the early 70s. Moreover, the presence or absence of respiratory movements, their amplitude and intervals testified to the condition of the fetus. However, FBM ultrasound did not gain popularity in the future.
In the early 80s, gynecologists from different countries conducted and presented a number of studies on the development of follicles and the ovulation process. Transvaginal scanning, the intensive introduction of which into gynecological practice began in the mid-80s, made it possible to see the opposite surface of the uterus, inaccessible with conventional ultrasound, and also made it possible to more accurately study ovulation cycles. However, the resolution of ultrasound as a method of visualizing the endometrium and follicles in those years did not yet fully determine the moment of ovulation in order to prevent pregnancy.
  Transvaginal ultrasound was an integral part of the diagnosis of non-palpable formations, ascites, uterine and cervical changes, early pregnancy, the presence and correctness of the introduction of intrauterine contraceptives. Since the late 80s, ultrasound (especially with the advent of color transvaginal scanning) has become a valuable method for diagnosing ectopic pregnancy, ovarian and endometrial cancer; vaginal ultrasound - an indispensable diagnostic method in the field of reproductology; spectral Doppler ultrasound (measurement of blood flow velocity using Doppler) - a standard study.
  In 1983, S. Campbell described the frequency index profile of a fetal Doppler scan. A year later, P. Reuwer (Netherlands) first revealed such an unfavorable sign of fetal development as the absence of a final diastolic blood flow in the umbilical artery. Further studies by S. Campbell's followers established the prognostic importance of such a sign as the absence of a final diastolic blood flow in the descending part of the fetal aorta. Later, other important discoveries were made with the help of Doppler ultrasound in obstetrics. As a result, the standard for detecting fetal oxygen starvation (anoxia) was ultrasound-Doppler examination of the umbilical artery; middle cerebral artery - to determine signs of decompensation; venous duct - for the diagnosis of acidosis, heart failure and the threat of fetal death. Also, with its help, the risk of uteroplacental insufficiency and preeclampsia in a pregnant woman was determined in the early stages.
In 1985, a clinician D. Maulik and professor of cardiology N. Nanda (USA) described intracardial blood flow using Doppler ultrasound. In 1987, an American researcher G. Devore created a color Doppler blood flow map to evaluate fetal malformations in practice. The use of color Doppler made it possible to make ultrasound of heart defects of the fetus more informative. In the late 90s, the accuracy of such diagnoses exceeded 95%.
  In 1989, a group of S. Campbell followers published a large-scale work on a 5-year ultrasound screening as one way to prevent ovarian cancer. Its results showed the significant role of ultrasound as a method for the timely diagnosis of cancer and the possibility of its use as a prophylactic screening of this pathology.
  As noted above, the emergence of new, more modern technologies in the 90s gave a powerful impetus to the development of ultrasound in medicine.
  M. Cullen (USA) was the first in 1990 to present a study of a large series of congenital malformations of the fetus in the first trimester, determined using transvaginal ultrasound. In those same years, thanks to the active introduction of transvaginal scanning into obstetric practice, sonoembryology began to develop actively.
  Ultrasound as a popular and sought-after diagnostic method contributed to a number of population screening programs in 1970-1990. The first of these was a screening program for maternal serum a-fetoprotein (Maternal serum alpha-fetoprotein, MSAFP) to detect neural tube blockage defects. She started in the UK in the late 70s. The second was a routine 20-week study of the fetus as part of the antenatal care program. A number of other various ultrasound screening studies were also conducted in the USA, Great Britain, Germany, Sweden, Norway, Finland and other European countries.
  Already at the end of the 90s, in Europe and the USA, ultrasound became the standard study, with which the gestational age was determined, twins were excluded, fetal malformations were revealed.
  It should be noted that ultrasound has also become a method for diagnosing developmental stigmas and signs of chromosomal abnormalities. Screening was based on the determination of various ultrasound parameters of such anomalies. So, the ultrasound diagnosis of such a chromosomal abnormality as Down syndrome began to develop actively. For the first time, transparency of the occipital bone of the fetus at a period of 15-20 weeks as a sign of Down syndrome was described by B. Benacerraf (USA) in 1985. Later, she published a list of ultrasound biometric markers of this pathology.

  3D ultrasound
With the development of computer technology, research on three-dimensional ultrasound has begun to improve. K. Baba (Japan) was the first to report the possibility of conducting a three-dimensional ultrasound in Japan in 1984, and two years later he received three-dimensional images using a two-dimensional ultrasound apparatus (Fig. 23). Soon, his research began to be put into practice. In 1992, K. Baba published the first book on ultrasound in obstetrics and gynecology, which included a section on three-dimensional scanning.
  A group of researchers led by D. King (USA) in 1990, unlike Japanese scientists, described a slightly different three-dimensional ultrasound algorithm. In 1992, Taiwanese clinicians Kuo, Chang, and Wu visualized the face, cerebellum, and cervical spine of a fetus using a Combison 330 scanner, which was created in 1989 and was the first three-dimensional ultrasound machine, using three-dimensional ultrasound. Soon in the mid-90s in Japan began to produce three-dimensional ultrasound machines. In 1993, the Austrian scientist W. Feichtinger performed an investigation of the embryo for a period of 10 weeks using three-dimensional transvaginal ultrasound. In subsequent years, three-dimensional ultrasound became one of the important research methods in obstetrics and gynecology. In 1996, a group of Nelson followers and scientists from College Hospital (UK) published an independent study on four-dimensional (moving three-dimensional) fetal echocardiography.
  Three-dimensional ultrasound compared with two-dimensional ultrasound had a number of diagnostic advantages, since it made it possible to determine a number of abnormalities of the fetus: lip splitting, polydactyly, micrognathia, malformations of the ear, spine and other developmental pathologies that can be detected by the appearance of the fetus. The development of transvaginal three-dimensional ultrasound has expanded the diagnostic capabilities of ultrasonography as a diagnostic method of the early stages of fetal development.
  In 1994, the Austrian obstetrician-gynecologist A. Lee, together with a group of followers Kratochwil, studied the accuracy of estimating fetal body mass using three-dimensional ultrasound and corrected the errors of the corresponding measurements of two-dimensional ultrasound. The use of three-dimensional ultrasound as a diagnostic method in gynecological practice was testified by the work of D. Jurkovic (Great Britain). In 1995, using this method, he diagnosed various uterine pathologies - a bicornuate uterus, septa in the uterus, etc.
A group of scientists from Taiwan led by F.-M. Chang in 1997 introduced a method for determining fetal body weight at birth using a three-dimensional ultrasound measurement of the fetal upper limb. A year later, H.-G. Blaas (Norway) published a work devoted to a three-dimensional study of the processes of embryogenesis, which confirmed the importance of this research method in embryology.
  The method of three-dimensional hysterography in the 90s began to study endometrial tissue, to diagnose endometrial formations, adhesions, hydrosalpingitis, ovarian cysts, small intrauterine tumors and other abnormalities of the female genital organs. According to the work of the Spanish clinician Bonilla-Musoles, the accuracy of the diagnosis of malignant ovarian neoplasms, determined using three-dimensional ultrasound, is almost 100% compared to two-dimensional.
  Color Doppler three-dimensional ultrasound made it possible to visualize the blood flow of tumors and therefore has become an effective method for diagnosing cervical and ovarian cancer.
  As you can see, ultrasound is a fairly new, but already an integral part of the diagnosis in obstetrics and gynecology. Within just a few decades, the use of ultrasound in medicine underwent pronounced changes: from diagnosing the presence of life in the uterine cavity to measuring the size of the fetus; from determining the morphology of the fetus to assessing its blood flow and developmental dynamics. Today, ultrasound continues to actively develop and improve.

* J. Woo. A Short History of the Development of Ultrasound in Obstetrics and Ginecology / http://www.ob-ultrasound.net/history1.html (full version)

References are in the wording