Mirror image artifact

Quick reference:↑ Cross-cutting acquisition and artifacts

View	Parasternal long axis beyond the pericardium; suprasternal aorta; subcostal IVC.
Timing	The mirrored copy is inverted and moves in the opposite direction to the true structure.
Caliper / trace	Not measured: identify the strong specular reflector in the beam path.

Example

Schematic sector panels: a ghost image at twice the depth of a reflector, and an inverted mirror image beyond the pericardium. — Mirror image beyond a specular reflector (right panel). (Schematic drawing (E/e′ureka), not a patient image)

Correct example

A duplicated mitral valve or LV wall beyond the pericardium in PLAX, or a double-barrelled aorta or IVC, recognized by its inversion and opposite motion relative to the real structure.

Common error

Calling the mirrored PLAX structures a left pleural effusion, or a duplicated vessel lumen a dissection flap.

Effect on interpretation

False effusions or flaps prompt unnecessary work-up; gain optimization and a change of plane or beam angle remove the reflector from the path or alter the reflection angle.

Why

Sound reflected off the specular surface strikes the structure and returns by the same detour, so the longer transit time is mapped as an inverted image on the far side of the reflector.