Which Doppler artifact is described as a duplication of the spectrum across the baseline?

Which Doppler artifact is described as a duplication of the spectrum across the baseline?

• A. Mirror imaging
• B. Aliasing
• C. Range ambiguity
• D. Spectral broadening

Answer: (A)

Mirror imaging is the Doppler artifact where a duplicate of the Doppler spectrum appears on the opposite side of the baseline, effectively mirroring the real spectrum across zero velocity. This ghost copy happens when a strong reflector in or near the imaging field creates an extra echo path that replays the Doppler signal into the display, producing a second, identical spectral trace on the other side of the baseline. You’ll see the same velocity distribution mirrored above and below zero velocity, even though only one flow pattern exists. This differs from aliasing, where high-velocity components wrap around the Nyquist limit and don’t form a neat mirror, and from range ambiguity or spectral broadening, which involve depth confusion or broadened spectra due to turbulence rather than a mirrored copy.

Mirror imaging is the Doppler artifact where a duplicate of the Doppler spectrum appears on the opposite side of the baseline, effectively mirroring the real spectrum across zero velocity. This ghost copy happens when a strong reflector in or near the imaging field creates an extra echo path that replays the Doppler signal into the display, producing a second, identical spectral trace on the other side of the baseline. You’ll see the same velocity distribution mirrored above and below zero velocity, even though only one flow pattern exists. This differs from aliasing, where high-velocity components wrap around the Nyquist limit and don’t form a neat mirror, and from range ambiguity or spectral broadening, which involve depth confusion or broadened spectra due to turbulence rather than a mirrored copy.