Question

How is the Doppler effect used to measure blood flow?

Answer 1

The Doppler effect is defined as a shift in frequency of a wave as a result of a moving observer relative to the wave source. It was named after Christian Doppler, an Austrian scientist who first reported the phenomena in 1842. The change in pitch perceived as a vehicle with a horn approaching and recedes from an observer is a frequent example of Doppler shift. The received frequency is greater during the approach, identical at the time of passing by, and lower during the recession as compared to the emitted frequency.

Complete answer:
A Doppler ultrasound examines the flow of blood through a blood vessel using reflected sound waves. It aids doctors in determining blood flow through main arteries and veins in the arms, legs, and neck. It might reveal obstructed or decreased blood flow through small regions in the neck's main arteries. This issue has the potential to result in a stroke. Blood clots in leg veins (deep vein thrombosis, or DVT) that might break loose and impede blood flow to the lungs can also be detected with this test. A pulmonary embolism is the medical term for this condition. During pregnancy, Doppler ultrasonography can be used to monitor the health of an unborn baby by looking at blood flow.
A portable instrument is softly passed over the skin above a blood artery during Doppler ultrasonography. A transducer is the name of the gadget. It uses a microphone to broadcast and receive sound waves that are amplified. Solid things, such as blood cells, bounce sound waves back. The pitch of reflected sound waves changes due to the movement of blood cells. The Doppler effect is the name for this phenomenon. The pitch does not alter if there is no blood flow. The data from reflected sound waves can be utilised to create graphs or images depicting blood flow through blood vessels. These graphs or images can be saved and re-examined at a later time.

Note:
Although "Doppler" has become associated with "velocity measurement" in medical imaging, the phase shift of the received signal is often quantified rather than the frequency shift (Doppler shift). Other disciplines of medical ultrasonography, such as obstetric ultrasonography and neurology, employ velocity measures of blood flow. The Doppler effect-based velocity assessment of blood flow in arteries and veins is a useful technique for diagnosing vascular issues including stenosis.