In spectral Doppler, which axis is used to plot velocity?

In spectral Doppler, which axis is used to plot velocity?

• A. Y-axis
• B. X-axis
• C. Z-axis
• D. Time axis

Answer: (A)

Velocity is plotted on the vertical axis in spectral Doppler. The horizontal axis represents time, so you can see how velocity changes throughout the cardiac cycle. This arrangement lets you observe the range and direction of flow at any moment: velocities toward the transducer appear on one side of the baseline and velocities away on the other, with zero velocity at the baseline. The depth of the sample volume is not depicted in this display; it’s set from the B-mode image and affects the position you sample from, not the velocity plot.

Velocity is plotted on the vertical axis in spectral Doppler. The horizontal axis represents time, so you can see how velocity changes throughout the cardiac cycle. This arrangement lets you observe the range and direction of flow at any moment: velocities toward the transducer appear on one side of the baseline and velocities away on the other, with zero velocity at the baseline. The depth of the sample volume is not depicted in this display; it’s set from the B-mode image and affects the position you sample from, not the velocity plot.