Pictorial EssayReflections on the Ultrasound Mirror Image ArtifactKerr, Dana Middleton MD∗; Middleton, William Dana MD†Author Information ∗Department of Radiology, Duke University, Durham, NC †Mallinckrodt Institute of Radiology, Washington University in St. Louis, St. Louis, MO. Received for publication April 23, 2020; accepted June 12, 2020. The authors declare no conflict of interest. Address correspondence to: William Dana Middleton, MD, Washington University in St. Louis Mallinckrodt Institute of Radiology, 510 South Kingshighway Blvd., St. Louis, MO 63110 (e-mail: [email protected]). Supplemental digital contents are available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal’s Web site (www.ultrasound-quarterly.com). Ultrasound Quarterly: December 2020 - Volume 36 - Issue 4 - p 287-299 doi: 10.1097/RUQ.0000000000000525 Buy SDC Metrics Abstract A key assumption in ultrasound is that the reflected echoes that return to the transducer travel in a straight line. Mirror image artifacts occur when the transmitted pulse and returning echo reflect off of a highly reflective interface (an acoustic mirror) and change direction before returning to the transducer, thereby breaking this assumption. Mirror image artifacts are seen throughout the body on gray scale, color Doppler, power Doppler, and spectral Doppler. They may closely duplicate the true structure in shape and echo strength, may distort the true structure, may appear weaker than the true structure, or may appear on images that do not simultaneously show the true structure. If not properly recognized, mirror image artifacts can be misinterpreted as true pathology and lead to additional unnecessary tests and potentially harmful interventions. Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.