The gray-scale variation in a pulsed-wave Doppler spectrum primarily represents what?

The gray-scale variation in a pulsed-wave Doppler spectrum primarily represents what?

• A. The number of red blood cells creating the reflection.
• B. The velocity of red blood cells.
• C. The speed of red blood cells.
• D. The ensemble length.

Answer: (B)

Gray-scale variation in a pulsed-wave Doppler spectrum reflects the strength of the Doppler signal at each velocity, which corresponds to how many red blood cells are moving at that velocity. Because the vertical axis represents velocity, the shading across the spectrum shows the distribution of blood flow speeds over time. In other words, you’re interpreting the velocity of the moving cells, not just counting cells or focusing on the pulse sequence length.

Gray-scale variation in a pulsed-wave Doppler spectrum reflects the strength of the Doppler signal at each velocity, which corresponds to how many red blood cells are moving at that velocity. Because the vertical axis represents velocity, the shading across the spectrum shows the distribution of blood flow speeds over time. In other words, you’re interpreting the velocity of the moving cells, not just counting cells or focusing on the pulse sequence length.