1. To obtain information on the spatial classification
(1) one-dimensional information equipment such as A-type, M-type, D-type.
(2) Two-dimensional information devices such as fan scanning B-type, linear scanning B-type, convex array scanning B-type.
(3) three-dimensional information equipment that is three-dimensional ultrasound equipment.
2. According to the ultrasound waveform classification
(1) continuous wave ultrasound equipment, such as continuous wave ultrasound multispectral flow meter.
(2) pulsed-wave ultrasound equipment such as A-type, M-type, B-type ultrasound diagnostic equipment.
3. Classified according to the utilization of the physical characteristics
(1) Echo ultrasound diagnostic equipment such as A-type, M-type, B-type, D-type.
(2) transmission ultrasound diagnostic equipment such as ultrasound microscopy and ultrasound holographic imaging system.
4. Classification of medical ultrasound equipment system
(1) A-type ultrasound diagnostic equipment will produce ultrasound pulse transducer placed on the surface of the human body at a certain point, the acoustic beam into the body, the amplitude of the signal returned by the tissue interface, displayed on the screen, the screen's horizontal coordinates of the ultrasound propagation time, that is, the depth of detection, the vertical coordinates of the amplitude of the return pulse ( The horizontal coordinate of the screen indicates the propagation time of the ultrasound, i.e. the depth of detection, and the vertical coordinate indicates the amplitude of the echo pulse ( amplitude), so it is called A type.
(2) M-type ultrasound diagnostic instrument A-type method of obtaining the echo information, brightness modulation method, added to the CRT cathode (or gate), and in the time axis to be unfolded, you can get the interface motion (motion) of the trajectory of the map, especially for the heart and other organs of the movement of the examination.
(3) B-type ultrasound diagnostic instrument, also known as B-type ultrasound cross-sectional imaging instrument, which modulates the amplitude of the echo pulse monitor brightness, and the horizontal and vertical coordinates of the monitor and the position of the speed of sound scanning corresponds to the position of the formation of a picture of the amplitude of brightness (brightness) modulation of ultrasound cross-sectional image. Therefore, it is called B. B-type ultrasound diagnostic instrument can be divided into the following categories: ① fan scanning B-type ultrasound diagnostic instrument ---- including high-speed mechanical fan scanning, convex array fan scanning, phased array fan scanning, etc.; ② linear scanning B-type ultrasound diagnostic instrument; ③ composite B-type ultrasound diagnostic instrument ---- which includes the composite of linear scanning and fan scanning, as well as the composite of the A-type, B-type, D-type and other modes of operation, which greatly enhance the functionality of the B-type ultrasound equipment, and thus improve the quality of the ultrasound scanning system. Enhances the function of B-type ultrasound equipment.
(4)D-type ultrasound Doppler diagnostic equipment Using the Doppler effect, the information of the moving tissues in the human body is detected, and the Doppler detection method is divided into continuous wave Doppler (CW) and pulse Doppler (PW).
(5) C-type and F-type ultrasound imager C-type probe movement and its synchronized scanning in the shape of a "Z", the display of the acoustic image is perpendicular to the direction of the acoustic beam, that is, equivalent to the X-ray tomography, and the F-type is a curved surface of the C-type form of a number of sections of the image constitutes a curved surface image, which is similar to a three-dimensional image.
(6)Ultrasonic holography diagnostic instrument It is along the introduction of the concept of optical holography, the application of two beams of ultrasound interference and diffraction to obtain ultrasonic amplitude and phase information, and laser reproduces the amplitude and phase.
(7) Ultrasound CT Ultrasound CT is the transplantation and development of X-CT theory, the use of ultrasound beams instead of X-rays, and the transmission data from the image reconstruction as X-CT, it becomes ultrasound CT, the advantages of which are: ① no radiation damage; ② can be obtained with the diagnostic information in different forms of X-CT and other ultrasound methods.
In short, with the medical progress and the development of ultrasound technology, a variety of new medical ultrasound equipment will continue to emerge.
A type of ultrasound echo display
A type of ultrasound diagnostic instrument because of its echo display using amplitude modulation (amplitude modulation) and the name. A type of ultrasound diagnostic instrument is one of the most basic display, that is, in the cathode ray tube (CRT) fluorescent screen, the horizontal coordinates represent the depth of the object being detected, the vertical coordinate represents the echo pulse The amplitude of the echo pulse, so by the probe (transducer) fixed-point emission to obtain the location of the echo can be measured by the thickness of the human organ, the depth of the lesion in the human tissue and the size of the lesion. Based on some other characteristics of the echo, such as wave amplitude and wave density, the lesion can also be characterized to some extent.
The A-type ultrasound diagnostic instrument is adapted to the examination of various medical disciplines, from the human brain up to the internal organs. One of the most used is the examination of liver, gallbladder, spleen, kidney and uterus. For some ophthalmologic diseases, especially for intraocular foreign bodies, the A-type ultrasound diagnostic instrument is more convenient and accurate than X-ray fluoroscopy. In obstetrics and gynecology, it is also more accurate and convenient for women's pregnancy examination and uterine mass examination.
Because the A-type display of the echo map, can only reflect the local tissue echo information, can not get in the clinical diagnosis of anatomical graphics, and the accuracy of the diagnosis and the operator of the map experience has a lot to do with the value of its application has been gradually seen to decline, even in the country, the A-type ultrasound diagnostic instrument is rarely produced and used.
Second, M-type ultrasound displayM-type ultrasound imaging diagnostic instrument for the movement of organs, such as cardiac exploration. Because the image is displayed by the motion echo signal on the monitor scan line to implement the glow modulation, and in chronological order to obtain a one-dimensional space multi-point motion timing (motion-time) map, so it is called M-type ultrasound imaging diagnostic equipment, the resulting image is also called echocardiography.
M-type ultrasound diagnostic instrument transmission and reception principle of operation, see Figure 7-12 (a), and some similar to the A-type, but the difference is its display. For the moving organs, because the position of the reflective echoes from all walks of life and the size of the signal is changing over time, if the amplitude modulation of the A-type display is still used for display, the displayed waveform will change over time, and do not get a stable waveform. Therefore, the M ultrasound diagnostic instrument using the method of glow modulation, so that the depth direction of all interface reflection echo, with the form of a bright spot in the display of the vertical scanning line shows, with the movement of the organ, the vertical scanning line of the points will occur on the position of the change, timed sampling of these echoes and make it according to the time successive line by line in the screen shows it. Figure 7-12(b) shows a graph of the activity of the reflective interfaces in the heart as measured during cardiac tachycardia. It can be seen that the interval of the activity curves changes due to changes in the movement of the organ, and if one of the interfaces in the organ is stationary, the activity curve will become a horizontal straight line.
M-type ultrasound diagnostic equipment for the human body in the movement of organs, such as the heart, fetal fetal heart, arterial vascular function of the examination has the advantage, and can be carried out a variety of cardiac function parameters of measurement, such as heart valve movement speed, acceleration, etc.. However, the M-display still cannot obtain anatomical images, and it is not suitable for the diagnosis and examination of static organs.
Three, B-type ultrasound imaging display
In order to obtain anatomical images of human tissues and organs, following the A-type ultrasound diagnostic instrument used in clinical practice, B-type, P-type, BP-type, C-type and F-type ultrasound imaging instrument has been introduced, due to one of their *** with the same characteristics of the human body to achieve a tomographic display of the tissues and organs, usually referred to as this type of instrument ultrasound tomography diagnostic instrument. Diagnostic instrument.
While the B-type ultrasound imaging diagnostic instrument because of its imaging method using brightness modulation (brightness modulation) and named, its image is displayed by the human body tissue or organs of the two-dimensional ultrasound tomography (or cross-section), for the movement of organs, but also real-time dynamic display, so the B-type ultrasound imaging instrument and the A-type, M-type ultrasound diagnostic instrument in the structure of the The principle are quite different.
The B-type ultrasound imager and the M-type as the same way to display the depth direction of all interfaces reflective echo, but the ultrasound beam emitted by the probe in the horizontal direction is a fast electronic scanning method (equivalent to rapid and equal interval to change the position of the A-ultrasound probe in the human body), one by one to obtain the depth of all interfaces of the depth direction of the reflective echo of the different positions, when a frame scanning is completed, you can get a picture of the direction of scanning by the ultrasound beam. When a scanning frame is completed, a vertical planar two-dimensional ultrasound tomographic image determined by the scanning direction of the ultrasound beam can be obtained, which is called a linear scanning tomographic image. Can also be changed by changing the angle of the probe (mechanical or electronic methods), so that the ultrasound beam pointing azimuth rapid change, so that every certain small angle, the direction of detection of all the interfaces of different depths of the reflected echo, are displayed in the form of bright spots in the corresponding scanning line, you can form a two-dimensional ultrasound tomographic image of a vertical sector determined by the direction of the probe oscillating, known as the sector scanning tomographic image.
If the 2 types of ultrasound images mentioned above have a fairly fast beam scanning speed for obtaining echo information, they can satisfy the stable sampling of the moving organs, and thus, the continuous scanning can realize the real-time dynamic display and observation of the dynamic situation of the moving organs.
Line scanning tomography B-type ultrasonic diagnostic instrument is suitable for observation of abdominal organs, such as the liver, gallbladder, spleen, kidneys, uterus examination, while the fan scanning tomography B-type ultrasonic diagnostic instrument is suitable for the examination of the heart. Modern B-type ultrasonic diagnostic instrument usually has the above 2 kinds of probing functions at the same time, through the use of different ultrasound probes, convenient conversion. Figure 7-13 shows 2 types of ultrasound tomographic images.
Four, D-type ultrasound imaging display
D-type ultrasound imaging diagnostic instrument, also known as ultrasound Doppler diagnostic instrument, which is the use of acoustic Doppler principle, the movement of the organs and the blood of the Doppler frequency shift signals of the reflected back signal to detect and process, converted into sound, waveforms, color and brightness signals, so as to display the movement of the human body's internal organs state. Ultrasound Doppler diagnostic equipment is mainly divided into three types: continuous wave Doppler imaging diagnostic equipment, pulsed wave Doppler imaging diagnostic equipment and real-time two-dimensional color Doppler flow image diagnostic equipment.
Continuous ultrasound Doppler imaging was the first to be used. It consists of a transducer in the probe that emits a continuous ultrasound signal at a certain frequency, and when the sound wave encounters a population of red blood cells in the moving target blood stream, the reflected signal is already a changed frequency ultrasound. Another transducer in the probe will be detected into an electrical signal sent to the host, after high-frequency amplification and the original frequency of the electrical signal for mixing, demodulation, and take out the difference in frequency signals according to the processing and display of different ways, can be converted into sound, waveforms, or blood flow chart for diagnosis. This way because it is difficult to determine the distance, can not determine the location of organs and tissues, to the application of diagnosis caused many inconveniences.
Pulsed ultrasound Doppler imagers emit ultrasound signals in an intermittent manner, hence the name pulsed. It is controlled by the gate control circuit to control the generation of the transmit signal and selective echo signal reception and amplification, with the help of intercepting the echo signal of the time period to select the determination of the distance, to identify the location of organs and tissues. As the emitted and received signals are pulsed, a transducer within the probe can be used to accomplish the dual tasks of emission and reception, which is very useful for simplifying the mechanical structure of the probe, avoiding undesirable coupling between the received and emitted signals, and improving the image quality. With the adoption and development of pulse Doppler technology, directional detection, spectral processing and computer coding technology, ultrasound Doppler diagnostic equipment is not only able to distinguish the distance, but also able to determine the direction and speed of blood flow, and provide diagnostic information to doctors in a variety of forms, so as to make its level of measurement from the qualitative to quantitative.
Real-time two-dimensional color Doppler flow imaging is the latest technological achievement in the field of cardiovascular ultrasound Doppler diagnosis in the late 1980s. It combines pulsed Doppler technology with two-dimensional (B-mode) real-time ultrasound imaging and M-mode echocardiography to provide information about the cardiovascular system in time and space by simultaneously showing the direction and relative velocity of blood flow on an intuitive two-dimensional cross-section of real-time images. In addition, through the computer's digital technology and image processing technology, the diagnostic imaging instrument's structure with physiological monitoring functions, to provide such as blood flow velocity, volume, flow, acceleration, vascular diameter, arterial index and other valuable information; this is commonly known as "color ultrasound" or "color Doppler". Color Doppler".