What is the principle of ultrasound Doppler imaging?

Ultrasound Doppler imaging uses the Doppler effect to measure blood flow velocity.

Ultrasound Doppler imaging is a medical imaging technique that uses the Doppler effect to measure blood flow velocity. The Doppler effect is the change in frequency of sound waves when the source of the waves and the observer are moving relative to each other. In the case of ultrasound Doppler imaging, sound waves are emitted from a transducer and directed towards the area of interest, such as a blood vessel. The sound waves bounce off the moving blood cells and return to the transducer. The frequency of the returning sound waves is compared to the frequency of the emitted sound waves, and the difference in frequency is used to calculate the velocity of the blood flow.

There are two types of Doppler ultrasound imaging: pulsed-wave Doppler and continuous-wave Doppler. Pulsed-wave Doppler uses short bursts of ultrasound waves to measure blood flow velocity at a specific location, while continuous-wave Doppler uses a continuous stream of ultrasound waves to measure blood flow velocity along a larger area. Doppler ultrasound imaging is commonly used to diagnose conditions such as deep vein thrombosis, peripheral arterial disease, and heart valve problems.

In addition to measuring blood flow velocity, ultrasound Doppler imaging can also provide information about the direction of blood flow and the presence of any obstructions or abnormalities in the blood vessels. It is a non-invasive and safe imaging technique that does not use ionizing radiation, making it a valuable tool in medical diagnosis and treatment.