How does ultrasound measure blood flow?

Ultrasound measures blood flow by using Doppler effect to detect changes in frequency of reflected sound waves.

Ultrasound is a non-invasive imaging technique that uses high-frequency sound waves to produce images of internal body structures. It can also be used to measure blood flow in the body. The Doppler effect is used to detect changes in the frequency of reflected sound waves as they bounce off moving objects, such as red blood cells.

When sound waves are reflected off a stationary object, the frequency of the reflected waves is the same as the frequency of the original waves. However, when the object is moving, the frequency of the reflected waves changes. If the object is moving towards the source of the sound waves, the frequency of the reflected waves increases. If the object is moving away from the source, the frequency of the reflected waves decreases.

In the case of blood flow, ultrasound is used to send sound waves into the body and the reflected waves are analysed to determine the direction and speed of blood flow. The frequency shift of the reflected waves is used to calculate the velocity of the blood flow. This information can be used to diagnose conditions such as blood clots, arterial stenosis, and venous insufficiency.

In conclusion, ultrasound uses the Doppler effect to measure blood flow by detecting changes in the frequency of reflected sound waves. This non-invasive technique is widely used in medical imaging to diagnose and monitor a variety of conditions.