Power Doppler versus velocity imaging: which statement is correct?

Power Doppler versus velocity imaging: which statement is correct?

• A. It shows only spectral data
• B. It is not angle dependent and more sensitive to slow flow
• C. It is angle dependent and less sensitive to slow flow
• D. It measures velocity directly

Answer: (B)

Power Doppler (color Doppler energy) measures the strength or power of the Doppler signal rather than the exact frequency shift. Because it sums Doppler energy from all moving blood cells, it is less affected by the angle between the beam and the flow and it is more sensitive to slow flow, making it good for detecting flow in small vessels or in low-velocity states. However, it does not provide direct velocity or direction information, which is why spectral data and velocity measurements are not part of Power Doppler. The other statements either imply angle sensitivity or claim velocity is measured directly, which aligns with velocity imaging rather than Power Doppler.

Power Doppler (color Doppler energy) measures the strength or power of the Doppler signal rather than the exact frequency shift. Because it sums Doppler energy from all moving blood cells, it is less affected by the angle between the beam and the flow and it is more sensitive to slow flow, making it good for detecting flow in small vessels or in low-velocity states. However, it does not provide direct velocity or direction information, which is why spectral data and velocity measurements are not part of Power Doppler. The other statements either imply angle sensitivity or claim velocity is measured directly, which aligns with velocity imaging rather than Power Doppler.