Doppler Ultrasound
Doppler ultrasound is based upon the Doppler Effect. When the object reflecting the sound waves is moving, it changes the frequency of the echoes. It creates higher frequency when it moves towards the probe and lower frequency when moving away from the probe. The change in the frequency depends on how fast the object is moving. This is a special technique mainly used to examine blood flow. Problems in the veins and arteries are detected by Doppler ultrasound. Doppler ultrasound is also used to measure the blood flow through the heart. The direction of the blood flow is shown in different colors on the ultrasound machine screen. The Doppler images help the physician to see and evaluate blockages to blood flow, such as clots, narrowing of vessels, which may be caused by plaque and such diseases. Tumors and congenital malformation are also detected by Doppler ultrasound.
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