Mirror image artifact
Citation, DOI & article data
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 angle of insonation of the primary ultrasound beam.
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- 2. Sandler MA, Madrazo BL, Walter R et-al. Ultrasound case of the day. Duplication artifact (mirror image artifact). Radiographics. 1988;7 (5): 1025-8. Pubmed citation
- 3. Ahn H, Hernández-Andrade E, Romero R, Ptwardhan M, Goncalves LF, Aurioles-Garibay A, Garcia M, Hassan SS, Yeo L. Mirror artifacts in obstetric ultrasound: case presentation of a ghost twin during the second-trimester ultrasound scan. (2013) Fetal diagnosis and therapy. 34 (4): 248-52. doi:10.1159/000353702 - Pubmed