Which artifact can appear as a mirror image of the Doppler spectrum across the baseline?

• A. Spectral broadening
• B. Bruit
• C. Mirror imaging
• D. Aliasing

Answer: (C)

Mirror image artifacts occur when a strong reflector in the image path causes a duplicate of the Doppler signal to appear on the opposite side of the velocity baseline. In spectral Doppler, velocities are plotted around zero, with flow toward the transducer above the baseline and flow away below it. A mirror image across this baseline means a copy of the spectrum appears mirrored across zero velocity, producing a symmetrical duplication of the spectrum. This is exactly what the question describes.

Spectral broadening is an overall widening of the spectral trace due to turbulence or a range of velocities, not a duplicated mirror. Bruit relates to a vascular sound and is not a Doppler spectral artifact. Aliasing is a separate artifact where high velocities wrap around the Nyquist limit, which can look similar in some contexts but is not described as a mirror image across the baseline like a true mirror imaging artifact.