What is spectral mirroring artifact?

• A. An artifact mirrored about the spectral baseline that can appear above or below the baseline
• B. A color Doppler artifact indicating aliasing
• C. Spectral mirroring artifact: artifactual mirrored about the spectral baseline; can appear above or below depending on baseline shift
• D. A true high-velocity signal

Answer: (C)

Spectral mirroring artifact is a duplicated, artifactual copy of the Doppler spectrum that is mirrored across the spectral baseline (the zero-velocity line). Because of how the spectrum is displayed, this mirror image can appear on the opposite side of the baseline, so its position relative to the true spectrum depends on how the baseline is shifted during recording or processing. It isn’t real blood flow; it comes from processing or filtering artifacts that cause the spectrum to be reflected. You can often recognize it by the mirrored, identical appearance across baseline and by adjusting baseline position, gain, or wall filtering to reduce or remove the artifact.