Which component is NOT part of the spectral Doppler display information?

The correct answer highlights that depth is not represented on the x-axis of a spectral Doppler display. Instead, the spectral Doppler display is structured to provide a temporal perspective (time) on the x-axis. This is essential because it allows practitioners to visualize how the velocity of blood flow changes over time, which is critical for assessing hemodynamics.

In spectral Doppler displays, the y-axis typically represents the frequency shift, which correlates to the velocity of the moving red blood cells (RBCs). This correlation allows for an interpretation of blood flow characteristics, including direction and speed. The brightness of the pixels in the display reflects the density of red blood cells and their ability to reflect ultrasound waves, but this is not part of the axis representation.

Depth information is indeed a crucial aspect of ultrasound imaging but is indicated elsewhere in the Doppler system rather than shown on the spectral display axes. By focusing on time and frequency shifts, clinicians can effectively analyze the hemodynamic profile of blood flow without the need for depth representation on the x-axis.