Color and spectral Doppler mirror-image artifact of the subclavian artery.

The mirror-image artifact, which has been previously described in gray-scale sonographic imaging, is also readily visualized with both spectral and color Doppler flow imaging. In 10 consecutive healthy subjects, a mirror image of the subclavian artery was readily apparent at gray-scale, spectral Doppler, and color Doppler sonography. An experimental in vitro model was constructed to demonstrate that the lung apex, which is located immediately posterior to the subclavian artery, acts as the highly reflective acoustic interface to form this artifact. Knowledge of the presence of the mirror-image artifact should be helpful to the radiologist and sonographer in avoiding misinterpretation of this important pitfall in both spectral and color Doppler flow imaging of the subclavian region, where there is a plethora of branching vessels.