What technique measures the velocity of blood flow over a short duration in Doppler ultrasound?

• A. Pulsed wave Doppler
• B. Continuous wave Doppler
• C. Color Doppler
• D. Power Doppler

Answer: (A)

Pulsed wave Doppler is the technique that measures the velocity of blood flow over a short duration in Doppler ultrasound. This method employs a pulsed ultrasound beam, allowing for the assessment of blood flow at specific locations along the vessel. By sending and receiving pulses of sound waves, it captures the velocity of blood flow within a designated sample volume, enabling precise measurements at a particular point in time. This makes pulsed wave Doppler particularly useful for analyzing quickly changing flow dynamics, such as those seen in cardiac or vascular studies.

In contrast, continuous wave Doppler continuously emits and receives sound waves, allowing it to measure high-velocity blood flow accurately but at the cost of specificity regarding the location of measurement. Color Doppler provides a visual representation of blood flow direction and velocity over a broader area, using color-coded images but does not measure the velocity directly in the same manner as pulsed wave Doppler. Power Doppler primarily assesses blood flow based on the strength of the Doppler signal, which can detect low-velocity flow but lacks the ability to provide specific velocity measurements.