Power Doppler is best described as?

• A. Identifies low flow blood vessels by reading reflection of RBCs in vessels
• B. Shows speed and direction of flow using color hues
• C. Assesses tissue stiffness
• D. Measures peak systolic velocity

Answer: (A)

Power Doppler detects the amount of Doppler signal energy produced by moving red blood cells, making it especially sensitive to slow or small-vessel flow. Because it encodes signal strength (not velocity), it highlights vessels with low flow by the brightness of the color, reflecting how many RBCs are moving rather than how fast they move. It does not provide information on flow speed or direction, unlike standard color Doppler or spectral Doppler, and it doesn’t measure tissue stiffness. This focus on signal amplitude from moving RBCs is why it’s best described as identifying low flow blood vessels by reading the reflection (energy) from RBCs within vessels.