Mirror image artifact

Andrew Murphy and Dr Ayush Goel et al.

Mirror image artifact in sonography is seen when there is a highly reflective surface (e.g. diaphragm) in the path of the primary beam.

The primary beam reflects from such a surface (e.g. diaphragm) but instead of directly being received by the transducer, it encounters another structure (e.g. a nodular lesion) in its path and is reflected back to the highly reflective surface (e.g. diaphragm). It then again reflects back towards the transducer.

The ultrasound machine makes a false assumption that the returning echo has been reflected once and hence the delayed echoes are judged as if being returned from a deeper structure, thus giving a mirror artifact on the other side of the reflective surface.

It is a friendly artifact that allows the sonographer to exclude pleural effusion by the reflection of the liver image through the diaphragm.


  • reflection of a liver lesion into the thorax (the commonest example)
  • reflection of abdominal ascites mimicking pleural effusion
  • duplication of gestational sac (either ghost twin or heterotopic pregnancy) 3
  • duplication of the uterus

To avoid this artifact, change the position and angle of scanning to change the angel of insonation of the primary ultrasound beam.

See also

Imaging technology

Article information

rID: 26561
Synonyms or Alternate Spellings:
  • Duplication artifact
  • Mirror image artefact
  • Mirror image artefacts
  • Mirror image artifacts
  • Mirror image artefact - ultrasound
  • Mirror image artifact - ultrasound

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Cases and figures

  • Case 1: liver lesion
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  • Case 2: mimicking pleural effusion
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  • Case 3: scrotum
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  • Case 4: scrotum
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