Ultrasonic diagnosis
Medical ultrasonic diagnostic instrument is a medical instrument which combines sonar principle and radar technology for clinical application. The basic principle is that high frequency ultrasonic pulse wave radiates into the organism, and different waveforms are reflected from different interfaces in the organism to form images. So as to determine whether there are lesions in the organism. The ultrasonic diagnostic instrument has developed from the original one-dimensional ultrasonic scanning display to the two-dimensional three-dimensional and four-dimensional ultrasonic scanning and display, which greatly increases the echo information and makes the lesions in the biological body clear and easy to distinguish. Therefore, it will be more and more widely used in medical ultrasonic diagnostic instrument.
1. One-dimensional ultrasonic scanning and display
In ultrasonic diagnosis equipment, people often refer to type A and Type M, which are diagnosed by ultrasonic pulse-echo distance measurement technology, as one-dimensional ultrasonic examination. The direction of this type of ultrasonic emission is unchanged, and the amplitude or gray scale of the signal reflected back from the non-simultaneous impedance interface is different. After amplification, it is displayed horizontally or vertically on the screen. This kind of image is called one-dimensional ultrasonic image.
(1) Type A ultrasound scan
Probe (transducer) according to the probe position, in a fixed way to the human body to emit several megahertz ultrasonic wave, through the human body echo reflection and amplification, and the echo amplitude and shape on the screen display. The vertical coordinate of the display shows the amplitude waveform of the reflection echo; There’s a time and distance scale on the abscissa. This can be based on the location of the echo, echo amplitude, shape, wave number and related information from the lesion and anatomical location of the subject for diagnosis. A – type ultrasonic probe in A fixed position can obtain the spectrum.
(2) M-type ultrasound scanner
The probe (transducer) transmits and receives an ultrasonic beam to the body in a fixed position and direction. The beam modulates the brightness of the vertical scan line of the display by passing through echo signals of different depths, and expands it in time order, forming a trajectory diagram of the movement of each point in one-dimensional space in time. This is the M-mode ultrasound. It can also be understood as: M-mode ultrasound is a one-dimensional track chart of time changes at different depth points along the same direction. M – scan system is especially suitable for the examination of motor organs. For example, in the examination of the heart, a variety of cardiac function parameters can be measured on the displayed graph trajectory, so m-mode ultrasound. Also known as echocardiography.
2. Two-dimensional ultrasonic scanning and display
Because one-dimensional scanning can only diagnose human organs according to the amplitude of ultrasonic return wave and the density of echo in the graph, one-dimensional ultrasound (a-type ultrasound) is greatly limited in ultrasonic medical diagnosis. The principle of two-dimensional ultrasonic scanning imaging is to use ultrasonic pulse echo, brightness adjustment of two-dimensional gray scale display, it vividly reflects the information of a section of the human body. Two-dimensional scanning system make the transducer to the human body in a fixed way inside the probe launched several MHZ ultrasound, and to a certain speed in a two-dimensional space, namely the scanned for two-dimensional space, then sent after the human body to amplify the echo signal processing to display cathode or control on the grid, the display of light spot brightness changes with the size of the echo signal, A two-dimensional tomography image is formed. When displayed on the screen, the ordinate represents the time or depth of the sound wave into the body, while the brightness is modulated by the amplitude of ultrasonic echo at the corresponding space point, and the abscissa represents the direction of the sound beam scanning the human body.
Post time: May-28-2022