1. A-mode ultrasonic echo display
The A-type ultrasonic diagnostic apparatus displays a clear sound wave display using amplitude modulation (amplitude modulation) names. The abyss of the detected organism, the ordinate represents the amplitude caused by the echo. Therefore, the thickness of the human organ, the depth of the lesion in the human tissue disease, and the basis of the lesion can be measured by the location (transducer) of the fixed point of the echo. Some other characteristics of the wave, such as the amplitude and size of the wave, can be used to qualitatively analyze the lesion to a certain extent.
A type of ultrasound diagnostic apparatus is adapted to medical examinations, from the human brain to hypoplasia. Among them, the application is mainly to check the liver, gallbladder, spleen, kidney, and uterus. For some diseases of ophthalmology, especially for intraocular abnormalities, fluoroscopy is more accurate than X-ray fluoroscopy. In obstetrics and gynecology, the examination of pregnant women and the examination of uterine masses are also more accurate and convenient.
Since the echo map displayed by Type A only has the echo information of the local tissue, it is impossible to obtain the required anatomical map in clinical diagnosis, and the accuracy of the diagnosis has a lot to do with the doctor's experience in image recognition, so its application value has gradually been seen. low,
2. M-mode ultrasound display
M-mode ultrasonic imaging diagnostic instrument is suitable for the exploration of sports organs, such as the heart. Since the displayed image is the brightness modulation of the display scan line by the motion echo signal, and it is expanded in time sequence to obtain a one-dimensional space multi-point motion time sequence (motion-time) diagram, so it is called M-mode ultrasound imaging diagnosis The resulting image is also called an echocardiogram.
The working principle of the transmitting and receiving of the M-type ultrasonic diagnostic apparatus is shown in Figure 7-12 (a). It is somewhat similar to the A-type, except for its display mode. For moving organs, since the position and signal size of the reflected echo from each interface change with time, if the amplitude-modulated A-type display mode is still used for display, the displayed waveform will change with time and cannot be stable. Waveform graph. Therefore, the M-type ultrasonic diagnostic apparatus adopts the brightness modulation method to reflect the echo of all interfaces in the depth direction, which is displayed on the vertical scan line of the display in the form of bright spots. With the movement of the organ, each point on the vertical scan line will be When position changes occur, these echoes are sampled regularly and displayed on the screen line by line according to time. Figure 7-12(b) is a graph of the activity curve of each reflection interface in the heart obtained when the heart beats. It can be seen that due to changes in the movement of the organ, the interval of the activity curve also changes accordingly. If an interface in the organ is stationary, the activity curve will become a horizontal straight line.、
