ARDMS SPI Color Doppler and Artifacts 2

Question 1

Which parameter, when increased, most effectively reduces color Doppler aliasing without changing the PRF?

Accepted Answer

Shift the baseline downward

Answer

Shifting the baseline extends the Nyquist limit in one direction, allowing higher velocities to be displayed without aliasing.

Question 2

A color Doppler image shows a mosaic pattern within a vessel lumen. This most likely indicates:

Accepted Answer

Turbulent or disturbed flow with aliasing

Answer

A mosaic pattern of mixed colors represents turbulent flow combined with aliasing, commonly seen distal to a stenosis.

Question 3

Which of the following best describes the color Doppler 'twinkling artifact'?

Accepted Answer

Rapidly alternating red and blue pixels behind a strongly reflective surface

Answer

The twinkling artifact produces rapidly flickering red and blue pixels posterior to calcifications or stones due to phase jitter.

Question 4

When the color Doppler gate is positioned at 90° to flow direction, the resulting color display will show:

Accepted Answer

No color signal

Answer

At 90° insonation angle the Doppler frequency shift is zero, so no color signal is generated.

Question 5

Color Doppler flash artifact is characterized by:

Accepted Answer

Transient color fill of entire image from tissue motion

Answer

Flash artifact occurs when patient or probe motion generates low-frequency Doppler shifts that briefly fill the color box with color.

ARDMS SPI - ARDMS Sonography Principles and Instrumentation Practice Test