Ultrasound procedure

The physical basis of ultrasound is the piezoelectric effect ^[2] . When single crystals of certain chemical compounds are deformed ( quartz , barium titanate ) under the influence of ultrasonic waves, opposite in sign electric charges arise on the surface of these crystals - a direct piezoelectric effect. When an alternating electric charge is applied to them, crystals oscillate with the emission of ultrasonic waves. Thus, one and the same piezoelectric element can be alternately either a receiver or a source of ultrasonic waves. This part in ultrasonic devices is called an acoustic transducer, transducer or sensor (the transducer sensor contains one or many quartz crystals, which are also called piezoelectric elements). The same crystals are used to receive and transmit sound waves. The sensor also has a sound-absorbing layer that filters sound waves, and an acoustic lens that allows you to focus on the desired wave.

Ultrasound propagates in media in the form of alternating zones of compression and expansion of matter. Sound waves, including ultrasound, are characterized by a period of oscillation - the duration of one full cycle of elastic oscillation of the medium; frequency - the number of oscillations per unit time; length - the distance between the points of one phase and the propagation velocity, which depends mainly on the elasticity and density of the medium. The wavelength is inversely proportional to its frequency. The higher the wave frequency, the higher the resolution of the ultrasonic sensor. In systems of medical ultrasound diagnostics, frequencies from 2 to 29 M Hz are usually used. The resolution of modern ultrasound devices can reach fractions of mm.

Any medium, including body tissue, prevents the spread of ultrasound, that is, it has various acoustic impedances , the magnitude of which depends on their density and the speed of propagation of sound waves. The higher these parameters, the greater the acoustic impedance. Such a general characteristic of any elastic medium is denoted by the term “ acoustic impedance ”.

Having reached the boundary of two media with different acoustic impedances, the ultrasonic wave beam undergoes significant changes: one part of it continues to propagate in the new medium, is absorbed to one degree or another by it, the other is reflected . The reflection coefficient depends on the difference in the acoustic resistance of the tissues adjacent to each other: the larger this difference, the greater the reflection and, naturally, the greater the intensity of the recorded signal, and therefore, the brighter and brighter it will look on the screen of the device. The full reflector is the boundary between the tissues and the air. ^[3]

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

Ultrasonic vibrations during propagation obey the laws of geometric optics . In a homogeneous medium, they propagate in a straight line and at a constant speed. At the boundary of various media with different acoustic densities, some of the rays are reflected, and some are refracted, continuing their rectilinear propagation. The higher the gradient of the difference in acoustic density of the boundary media, the greater part of the ultrasonic vibrations is reflected. Since 99.99% of vibrations are reflected at the interface between ultrasound from air and skin, ultrasound scanning of the patient requires lubrication of the skin surface with water jelly, which acts as a transition medium. Reflection depends on the angle of incidence of the beam (the largest in the perpendicular direction) and the frequency of ultrasonic vibrations (at a higher frequency, most are reflected).

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

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

When superimposed on the primary and reflected signals, beats occur that are heard using headphones or a loudspeaker.

Ultrasonic Wave Generator

An ultrasonic wave generator is a sensor that simultaneously plays the role of a receiver of reflected echo signals. The generator operates in a pulsed mode, sending about 1000 pulses per second. Between the generation of ultrasonic waves, the piezoelectric transducer captures the reflected signals.

Ultrasonic Sensor

As a detector or transducer, a complex sensor is used, consisting of several hundreds or thousands ^{[4] [5] of} small piezocrystalline transducers operating in the same or different modes, similar to digital antenna arrays . A focusing lens is mounted in the classic sensor, which makes it possible to create focus at a certain depth. Due to the digital beam formation in modern sensors, it is also possible to realize its dynamic focusing in depth with multidimensional apodization ^{[4] [5]} .

Sensor Types

All ultrasonic sensors are divided into mechanical and electronic. In mechanical scanning is carried out due to the movement of the emitter (it either rotates or sways). In electronic scanning is carried out electronically. The disadvantages of mechanical sensors are noise, vibration produced by the movement of the emitter, as well as low resolution. Mechanical sensors are obsolete and are not used in modern scanners. Electronic sensors contain emitter gratings ^{[4] [5]} , for example, from 512 or 1024x4 elements ^{[4] [5]} , which, due to digital beam forming, provide three types of ultrasonic scanning: linear (parallel), convex and sector. Accordingly, the sensors or transducers of ultrasonic devices are called linear, convex and sector. The choice of sensor for each study is based on the depth and nature of the position of the organ.

Linear Sensors

Linear sensors use a frequency of 5-15 MHz. The advantage of a linear sensor is the full compliance of the organ under study with the position of the transducer itself on the surface of the body. The disadvantage of linear sensors is the difficulty in ensuring in all cases a uniform adherence of the transducer surface to the patient's skin, which leads to distortion of the resulting image at the edges. Also, linear sensors due to the higher frequency allow to obtain an image of the studied area with high resolution, however, the scanning depth is quite small (no more than 11 cm). They are used mainly for the study of superficially located structures - the thyroid gland, mammary glands, small joints and muscles, as well as for the study of blood vessels.

Convex sensors

Convex sensor uses a frequency of 1.8-7.5 MHz. It has a shorter length, so achieving uniformity of its fit to the patient’s skin is simpler. However, when using convex sensors, the resulting image is several centimeters wider than the dimensions of the sensor itself. To clarify the anatomical landmarks, the doctor must take into account this discrepancy. Due to the lower frequency, the scanning depth reaches 20-25 cm. It is usually used to study deeply located organs: organs of the abdominal cavity and retroperitoneal space, genitourinary system, and hip joints.

Sector Sensors

The sector sensor operates at a frequency of 1.5-5 MHz. There is an even greater discrepancy between the size of the transducer and the resulting image, therefore it is used mainly in cases where it is necessary to get a large view at a depth from a small area of ​​the body. The most appropriate use of sector scanning in the study, for example, through intercostal spaces. A typical application of a sector sensor is echocardiography - a study of the heart.

Ultrasonic Emission Gel

Unlike the audible range, ultrasound is noticeably attenuated and distorted by thin (fractions of mm) obstacles, and high resolution scanning is possible only with minimal distortion in the amplitude and time of sound propagation. With a simple attachment of the sensor, an air gap forms of constantly changing thickness and geometry. Ultrasound is reflected from both boundaries of the layer, weakening and interfering with a useful reflection. To eliminate reflective boundaries at the contact point, special gels are used that fill the area between the sensor and the skin.

Typical gel composition: glycerin, sodium tetraborate, styrene-maleic anhydride copolymer, purified water.

The reflected echoes enter the amplifier and special reconstruction systems, after which they appear on the monitor screen in the form of sections of the body with different shades of gray. With positive registration, the maximum intensity of the echo signals appears on the screen in white (echopositive areas), and the minimum in black (echo-negative areas). With negative registration, the opposite is observed. The choice of positive or negative registration is determined by the personal preferences of the operator. The image obtained during the study may be different depending on the operating modes of the scanner. The following modes are distinguished:

• A-mode ( English a mplitude ). The technique provides information in the form of a one-dimensional image, where the first coordinate is the amplitude of the reflected signal from the boundary of media with different acoustic impedances, and the second is the distance to this boundary. Knowing the speed of propagation of an ultrasonic wave in the tissues of a human body, it is possible to determine the distance to this zone by dividing in half (since the ultrasound beam travels this path twice) the product of the pulse return time and the speed of ultrasound.
• B-mode ( English b rightness ). The technique provides information in the form of two-dimensional seroscale tomographic images of anatomical structures in real time, which allows us to assess their morphological state.
• M-mode ( English m otion ). The technique provides information in the form of a one-dimensional image, the second coordinate is replaced by a temporary one. The vertical axis shows the distance from the sensor to the positioned structure, and the horizontal axis shows time. The regimen is used mainly for examining the heart. Provides information about the form of curves that reflect the amplitude and speed of movement of cardiac structures.

The technique is based on the use of the Doppler effect . The essence of the effect is that ultrasonic waves are reflected from moving objects with a changed frequency. This frequency shift is proportional to the speed of the located structures - if the movement is directed towards the sensor, then the frequency increases, if from the sensor it decreases.

There are blind dopplerography (not considered an ultrasound scan, performed as part of a functional diagnosis) and B-mode (modern).

The first obsolete version got its name due to the fact that the location of the flow (vessel) is selected based on the installation of the blind depth of the scan on the device, that is, the device has only Doppler mode, without B-mode, so it is impossible to determine exactly which vessel spectral data are obtained.

In modern ultrasound scanners, dopplerography, as a rule, is performed in duplex or even triplex mode, that is, first a vessel is in B-mode, then an area (control volume) of data measurement is set on it corresponding to the desired scanning depth and a stream spectrum is obtained.

Spectral Dopplerography

Designed to assess the movement of moving media. In particular, blood flow in relatively large vessels and chambers of the heart, heart walls. The main type of diagnostic information is spectrographic recording, which is a sweep of blood flow velocity over time. In such a graph, speed is plotted on the vertical axis, and time on the horizontal axis. The signals displayed above the horizontal axis come from the blood flow directed towards the sensor, below this axis from the sensor. In addition to the speed and direction of blood flow, the nature of the blood flow can be determined by the type of Doppler spectrogram: the laminar flow is displayed in the form of a narrow curve with clear contours, and the turbulent one - in a wide inhomogeneous curve.

Continuous (constant wave) spectral dopplerography

The technique is based on constant radiation and constant reception of reflected ultrasonic waves. The magnitude of the frequency shift of the reflected signal is determined by the movement of all structures in the path of the ultrasound beam within the depth of its penetration. Disadvantage: the impossibility of an isolated analysis of flows in a strictly defined place. Advantages: allows the measurement of high blood flow rates.

Pulse LED

The technique is based on the periodic emission of a series of pulses of ultrasonic waves, which, reflected from red blood cells, are sequentially sensed by the same sensor. In this mode, signals are recorded, reflected only from a certain distance from the sensor, which are set at the discretion of the doctor. The place of study of blood flow is called the control volume. Advantages: the ability to assess blood flow at any given point.

Tissue SD

It is similar to pulsed diabetes, only adapted not for blood flow, but for the myocardium (heart wall).

Color Doppler Mapping (CDM)

Based on color coding of the Doppler shift value of the emitted frequency. The technique provides a direct visualization of blood flows in the heart and in relatively large vessels. Red color corresponds to the flow going towards the sensor, blue - from the sensor. Dark shades of these colors correspond to low speeds, light shades - high. Disadvantage: the impossibility of obtaining images of small blood vessels with a low blood flow velocity. Advantages: allows you to evaluate both the morphological state of the vessels and the state of blood flow by them.

Energy Dopplerography (ED)

The technique is based on the analysis of the amplitudes of all echo signals of the Doppler spectrum, reflecting the density of red blood cells in a given volume. Shades of color (from dark orange to yellow) carry information about the intensity of the echo signal. The diagnostic value of energy dopplerography is the ability to assess vascularization of organs and pathological sites. Недостаток: невозможно судить о направлении, характере и скорости кровотока. Достоинства: отображение получают все сосуды, независимо от их хода относительно ультразвукового луча, в том числе кровеносные сосуды очень небольшого диаметра и с незначительной скоростью кровотока.

Комбинированные варианты

Применяются также и комбинированные варианты, в частности ЦДК+ЭД — конвергентная цветовая доплерография.

Трёхмерное доплеровское картирование и трёхмерная ЭД

Методики, дающие возможность наблюдать объемную картину пространственного расположения кровеносных сосудов в режиме реального времени в любом ракурсе, что позволяет с высокой точностью оценивать их соотношение с различными анатомическими структурами и патологическими процессами, в том числе со злокачественными опухолями. В этом режиме используется возможность запоминания нескольких кадров изображения. После включения режима исследователь перемещает датчик или изменяет его угловое положение, не нарушая контакта датчика с телом пациента. При этом записываются серии двухмерных эхограмм с небольшим шагом (малое расстояние между плоскостями сечения). На основе полученных кадров система реконструирует псевдотрёхмерное ^{[ неизвестный термин ]} изображение только цветной части изображения, характеризующее кровоток в сосудах. Поскольку при этом не строится реальная трехмерная модель объекта, при попытке изменения угла обзора появляются значительные геометрические искажения из-за того, что трудно обеспечить равномерное перемещение датчика вручную с нужной скоростью при регистрации информации. Метод позволяющий получать трёхмерные изображения без искажений, называется методом трёхмерной эхографии (3D).

Методика основана на внутривенном введении особых контрастирующих веществ, содержащих свободные микропузырьки газа (диаметром менее 5 мкм при их циркуляции не менее 5 минут). Полученное изображение фиксируется на экране монитора, а затем регистрируется с помощью принтера .

В клинической практике методика используется в двух направлениях.

Динамическая эхоконтрастная ангиография

Существенно улучшается визуализация кровотока, особенно в мелких глубоко расположенных сосудах с низкой скоростью кровотока; значительно повышается чувствительность ЦДК и ЭД; обеспечивается возможность наблюдения всех фаз контрастирования сосудов в режиме реального времени; возрастает точность оценки стенотических поражений кровеносных сосудов.

Тканевое эхоконтрастирование

Обеспечивается избирательностью включения эхоконтрастных веществ в структуру определённых органов. Степень, скорость и накопление эхоконтраста в неизменённых и патологических тканях различны. Появляется возможность оценки перфузии органов, улучшается контрастное разрешение между нормальной и пораженной тканью, что способствует повышению точности диагностики различных заболеваний, особенно злокачественных опухолей. ^[6]

Эхоэнцефалография

Эхоэнцефалография, как и доплерография, встречается в двух технических решениях: A-режим (в строгом смысле не считается ультразвуковым исследованием, входит в функциональную диагностику и в настоящее время практически не используется) и B-режим, получивший неофициальное название «нейросонография». Так как ультразвук не может эффективно проникать сквозь костную ткань, в том числе кости черепа, нейросонография выполняется только грудным детям через большой родничок .

Офтальмология

Также, как и эхоэнцефалография, существует в двух технических решениях (разные приборы): A-режим (обычно не считается УЗИ) и В-режим.

Ультразвуковые зонды применяются для измерения размеров глаза и определения положения хрусталика.

Внутренние болезни

Ультразвуковое исследование играет важную роль в постановке диагноза заболеваний внутренних органов, таких как:

• брюшная полость и забрюшинное пространство
  • печень
  • жёлчный пузырь и желчевыводящие пути
  • поджелудочная железа
  • селезёнка
  • the kidneys
• органы малого таза
  • мочеточники
  • мочевой пузырь
  • предстательная железа

Ввиду относительно невысокой стоимости и высокой доступности ультразвуковое исследование является широко используемым методом обследования пациента и позволяет диагностировать достаточно большое количество заболеваний, таких как онкологические заболевания, хронические диффузные изменения в органах (диффузные изменения в печени и поджелудочной железе, почках и паренхиме почек, предстательной железе, наличие конкрементов в желчном пузыре, почках, наличие аномалий внутренних органов, жидкостных образований в органах.

В силу физических особенностей не все органы можно достоверно исследовать ультразвуковым методом, например, полые органы желудочно-кишечного тракта труднодоступны для исследования из-за содержания в них газа. Тем не менее, ультразвуковая диагностика может применяться для определения признаков кишечной непроходимости и косвенных признаков спаечного процесса. При помощи ультразвукового исследования можно обнаружить наличие свободной жидкости в брюшной полости, если её достаточно много, что может играть решающую роль в лечебной тактике ряда терапевтических и хирургических заболеваний и травм.

Печень

Ультразвуковое исследование печени является достаточно высокоинформативным. Врачом оцениваются размеры печени, её структура и однородность, наличие очаговых изменений, а также состояние кровотока. УЗИ позволяет с достаточно высокой чувствительностью и специфичностью выявить как диффузные изменения печени (жировой гепатоз, хронический гепатит и цирроз), так и очаговые (жидкостные и опухолевые образования). Обязательно следует добавить, что любые ультразвуковые заключения исследования как печени, так и других органов, необходимо оценивать только вместе с клиническими, анамнестическими данными, а также данными дополнительных обследований.

Жёлчный пузырь и жёлчные протоки

Кроме самой печени оценивается состояние жёлчного пузыря и жёлчных протоков — исследуются их размеры, толщина стенок, проходимость, наличие конкрементов, состояние окружающих тканей. УЗИ позволяет в большинстве случаев определить наличие конкрементов в полости желчного пузыря.

Поджелудочная железа

При исследовании поджелудочной железы оцениваются её размеры, форма, контуры, однородность паренхимы, наличие образований. Качественное УЗИ поджелудочной железы часто довольно затруднительно, так как она может частично или полностью перекрываться газами, находящимися в желудке, тонком и толстом кишечнике. Наиболее часто выносимое врачами ультразвуковой диагностики заключение «диффузные изменения в поджелудочной железе» может отражать как возрастные изменения (склеротические, жировая инфильтрация), так и возможные изменения вследствие хронических воспалительных процессов.

Почки и надпочечники, забрюшинное пространство

Исследование забрюшинного пространства, почек и надпочечников является достаточно трудным для врача ввиду особенностей их расположения, сложности строения и многогранности и неоднозначности трактовки ультразвуковой картины этих органов. При исследовании почек оценивается их количество, расположение, размер, форма, контуры, структура паренхимы и чашечно-лоханочной системы. УЗИ позволяет выявить аномалии почек, наличие конкрементов, жидкостных и опухолевых образований, также изменения вследствие хронических и острых патологических процессов почек.

Щитовидная железа

In the study of the thyroid gland, ultrasound is the leading one and allows you to determine the presence of nodes, cysts, changes in the size and structure of the gland.

Cardiology, Vascular and Cardiac Surgery

Echocardiography (EchoCG) is an ultrasound diagnosis of heart disease. This study assesses the size of the heart and its individual structures (ventricles, atria, interventricular septum, thickness of the myocardium of the ventricles, atria, etc.), the presence and volume of fluid in the pericardial cavity, the state of the heart valves, and also, in the Doppler mode, blood flow in the heart and main vessels. Using special calculations and measurements, echocardiography allows you to determine the mass of the myocardium, the contractility of the heart (ejection fraction, cardiac output, etc.). Echocardiography is usually carried out through the chest (transthoracically), and there is also a transesophageal echocardiography (PE-Echocardiography) when a special endoscopic probe is placed in the esophagus. PE-EchoCG allows you to better see the heart, because the sensor is closer to the heart than with conventional echocardiography and therefore it becomes possible to use a sensor with a higher ultrasound frequency, which increases the resolution of the image. There are also special high-frequency intraoperative sensors that help during heart surgery.

The 4D EchoCG shown in the image allows you to get a live 3D image of the heart, i.e. in real time, which can also be useful, a special 4D sensor is required to carry out this technique.

Obstetrics, gynecology and prenatal diagnosis

An ultrasound study is used to study the internal genital organs of a woman, the state of the pregnant uterus, the anatomy and monitoring of fetal development.

This effect is widely used in obstetrics, since sounds coming from the uterus are easily recorded. In the early stages of pregnancy, sound travels through the bladder. When the uterus is filled with fluid, it itself begins to conduct sound. The position of the placenta is determined by the sounds of the blood flowing through it, and after 9 - 10 weeks from the moment the fetus is formed, the heartbeat is heard. Using ultrasound, you can also determine the number of embryos or ascertain the death of the fetus.

Danger and side effects

Ultrasound is generally considered a safe way to obtain information. ^[7]

Diagnostic ultrasound of the fetus is also generally regarded as a safe method for use during pregnancy. This diagnostic procedure should be used only if there is good medical evidence, with the shortest possible exposure time for ultrasound, which will allow you to obtain the necessary diagnostic information, that is, on the principle of the minimum acceptable or ALARA principle.

World Health Organization Report No. 875 of 1998 supports the view that ultrasound is harmless ^[8] . Despite the lack of data on the dangers of ultrasound to the fetus, the Food and Drug Administration (USA) considers the advertising, sale and rental of ultrasound equipment to create a “fetal memory video” as inappropriate, unauthorized use of medical equipment.

An ultrasound diagnostic apparatus (ultrasound scanner) is a device designed to obtain information about the location, shape, size, structure, blood supply to organs and tissues of humans and animals ^{[2] [4] [5]} .

According to the form factor, ultrasound scanners can be divided into stationary and portable (portable) ^{[4] [5]} ; by the mid-2010s, mobile ultrasound scanners based on smartphones and tablets became widespread.

Outdated Ultrasound Classification

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

• ETS - echotomoscopes (devices intended mainly for the study of the fetus, abdominal organs and small pelvis);
• EX - echocardioscopes (devices intended for the study of the heart);
• EES - echoenceloscopes (devices designed to study the brain);
• EOS - echophthalmoscopes (devices intended for the study of the eye).

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

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

Device Classifications

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

The term “ultrasound examination” in the strict sense can mean research in the B-mode, in particular, in Russia this is standardized and research in the A-mode is not considered an ultrasound. Devices of the old generation without B-mode are considered obsolete, but so far they are used as part of functional diagnostics.

The commercial classification of ultrasound machines basically does not have clear criteria and is determined independently by manufacturers and their dealer networks, characteristic equipment classes:

• Primary class (B-mode)
• Middle class (CDK)
• High class
• Premium class
• Expert class

Terms, concepts, abbreviations

• Advanced 3D is an advanced three-dimensional reconstruction program.
• ATO - automatic image optimization, optimizes image quality with the click of a button.
• B-Flow - visualization of blood flow directly in the B-mode without the use of Doppler methods.
• Coded Contrast Imaging Option - coded contrast image mode, used in the study with contrast agents.
• CodeScan is a technology for amplifying weak echo signals and suppressing unwanted frequencies (noise, artifacts) by creating an encoded sequence of pulses in a transmission with the possibility of decoding them at the reception using a programmable digital decoder. This technology allows you to achieve unrivaled image quality and improve diagnostic quality due to new scanning modes.
• Color doppler (CFM or CFA) - color doppler (Color Doppler) - emphasis on the echogram by color (color mapping) of the nature of blood flow in the area of ​​interest. It is customary to map the blood flow to the sensor in red, from the sensor in blue. Turbulent blood flow is mapped by a blue-green-yellow color. Color doppler is used to study blood flow in vessels, in echocardiography. Other technology names include color Doppler mapping (CDC), color flow mapping (CFM) and color flow angiography (CFA). Usually using color Doppler, changing the position of the sensor, find the area of ​​interest (vessel), then use a pulsed Doppler to quantify. Color and energy doppler help in the differentiation of cysts and tumors, since the inner contents of the cyst are devoid of blood vessels and, therefore, can never have color loci.
• DICOM - the ability to transfer raw data over the network for storage on servers and workstations, printouts and further analysis.
• Easy 3D - a mode of surface three-dimensional reconstruction with the ability to set the level of transparency.
• M-mode (M-mode) - a one-dimensional ultrasound scan mode (historically the first ultrasonic mode), in which anatomical structures are examined in a sweep along the time axis, is currently used in echocardiography. M-mode is used to assess the size and contractile function of the heart, the valve apparatus. Using this mode, it is possible to calculate the contractility of the left and right ventricles, to evaluate the kinetics of their walls.
• MPEGvue - quick access to stored digital data and a simplified procedure for transferring images and video clips to CD in a standard format for later viewing and analysis on a computer.
• Power doppler - energy doppler - a qualitative assessment of low-speed blood flow, used in the study of a network of small vessels (thyroid gland, kidneys, ovary), veins (liver, testicles), etc. It is more sensitive to the presence of blood flow than color doppler. The echogram is usually displayed in an orange palette, brighter shades indicate a greater blood flow velocity. The main drawback is the lack of information about the direction of blood flow. The use of energy doppler in three-dimensional mode allows one to judge the spatial structure of blood flow in the scan area. In echocardiography, energy doppler is rarely used, sometimes used in combination with contrast agents to study myocardial perfusion. Color and energy doppler help in the differentiation of cysts and tumors, since the inner contents of the cyst are devoid of blood vessels and, therefore, can never have color loci.
• Smart Stress - Advanced stress echo studies. Quantitative analysis and the ability to save all scan settings for each stage of the study when visualizing various segments of the heart.
• Tissue Harmonic Imaging (THI) is a technology for isolating the harmonic component of vibrations of internal organs caused by the passage of a basic ultrasound pulse through the body. Useful is the signal obtained by subtracting the base component from the reflected signal. The use of the 2nd harmonic is advisable for ultrasonic scanning through tissues intensively absorbing the 1st (basic) harmonic. The technology involves the use of broadband sensors and a receiving path of increased sensitivity, improving image quality, linear and contrast resolution in patients with increased weight. * Tissue Synchronization Imaging (TSI) is a specialized tool for diagnosing and evaluating cardiac dysfunctions.
• Tissue Velocity Imaging , Tissue Doppler Imaging (TDI) - tissue doppler - mapping of tissue movement, is used in TSD and TCDC (tissue spectral and color dopplerography) modes in echocardiography to assess myocardial contractility. By studying the direction of movement of the walls of the left and right ventricles in the systole and diastole of tissue Doppler, you can find hidden zones of violation of local contractility.
• Transducer is an acoustic transducer.
• TruAccess is an imaging approach based on the ability to access raw ultrasound data.
• TruSpeed is a unique set of software and hardware components for processing ultrasonic data, providing ideal image quality and the highest data processing speed in all scanning modes.
• Virtual Convex - advanced convex image using linear and sector sensors.
• VScan - visualization and quantification of myocardial movement.
• Pulse Doppler (PW, HFPW) - Pulse Doppler (Pulsed Wave or PW) is used to quantify blood flow in vessels. On a vertical scan, the flow velocity at the point under investigation is displayed vertically. Flows that move to the sensor are displayed above the baseline, reverse blood flow (from the sensor) is displayed below. The maximum flow rate depends on the scanning depth, pulse frequency and has a limitation (about 2.5 m / s for heart diagnostics). High-frequency pulsed doppler (HFPW - high frequency pulsed wave) allows you to register the flow velocity of a higher speed, but also has a limitation associated with the distortion of the Doppler spectrum.
• Constant Wave Doppler - Continuous Wave Doppler (CW) is used to quantify blood flow in vessels with high speed flows. The disadvantage of this method is that streams are recorded over the entire scanning depth. In echocardiography, with the help of a constant-wave Doppler, you can calculate the pressure in the cavities of the heart and the great vessels in one or another phase of the cardiac cycle, calculate the degree of significance of stenosis, etc. The basic CW equation is the Bernoulli equation, which allows you to calculate the pressure difference or pressure gradient. Using the equation, you can measure the pressure difference between the cameras in the norm and in the presence of pathological, high-speed blood flow.

• Ultrasound diagnostics
• Sonoelastography