Time : 2022-12-30
It is to use the Doppler effect produced by ultrasound in the blood flow in the human body.
The application of clinical diagnosis has been used for cardiac function examination since 1956. Later, the continuous wave Doppler method was used to find the beating sound of the fetal heart and check the carotid artery blood flow.
Because the Doppler information of blood flow can be obtained by ultrasonic pulses, the pulse Doppler method is widely used in B-type monitors and combined circulators.
This method is to display the two-dimensional distribution of blood flow in real time on the basis of B-type monitor images and M-type monitor images. Due to the appearance of the ultrasound machine using this method, the dangerous and invasive examination that is still used until now has been replaced in the diagnosis.
The continuous wave Doppler method is to continuously transmit ultrasonic waves to the target direction, detect the Doppler information from the received echo, and finally display it as a graphic. The transmission and reception of this method use independent vibrators to work continuously, and it is easy to detect Rapid blood flow is the biggest feature of this ultrasound machine.
The necessary echo can be arbitrarily selected and the Doppler information can be detected, which is the same as the above-mentioned continuous wave method, and it is a method of displaying graphics.
Because this method uses pulses, only one vibrator can be used to obtain B-type display information and Doppler information. While observing B-type images, the sampling gate pulse is used to determine the blood flow at any position, and more than one part can be obtained. Buller information is the biggest feature of this ultrasonic instrument, which can get the greatest possible blood flow velocity.