title: Duplication images in vascular sonography.
abstract: OBJECTIVE
  The purpose of this study was to determine the characteristics and phenomena of duplication (or mirror) images in vascular sonography.
  
  
  METHODS
  We retrospectively reviewed 5 cases of vascular sonography that produced duplication images performed between June 30, 2009, and January 10, 2010. The 5 vascular studies included the subclavian artery (2), subclavian vein (1), carotid artery (1), and abdominal aorta (1). The characteristics of the color flow images and spectral Doppler waveforms in the artifactual vessels and in the true vessels were analyzed. Sources and mechanisms of producing duplication images were assessed.
  
  
  RESULTS
  We were able to generate color flows in the artifactual vessels that were the same as in the true vessels in 2 cases. However, we were able to generate images in which the apparent flow directions in the artifactual vessels differed from the actual flow observed in the true vessels in all 5 cases by changing the orientation of the ultrasound beam relative to the true flow and the reflecting surface.
  
  
  CONCLUSIONS
  Duplication images result from mirror reflections producing multipath artifacts. The appearance of the flow in an artifactual vessel on color Doppler imaging strongly depends on the angle of the incident sound beam and the surface structure of the strong reflector relative to the flow in the true vessel. Alternating the scanning plane and the angle of the incident sound beam to the reflector may help distinguish a duplication artifact from a true vessel in ambiguous cases.
authors.affiliation: Department of Radiology, University Hospital, University of Michigan, Ann Arbor, MI 48109-5030 USA. jrubin@med.umich.edu
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Rubin
authors.forename: Jing
authors.initials: J
authors.lastname: Gao
authors.forename: Keith
authors.initials: K
authors.lastname: Hetel
authors.forename: Robert
authors.initials: R
authors.lastname: Min
mesh_terms: D001012:Aorta, Abdominal / Q000000981:diagnostic imaging; D001158:Arteries / Q000000981:diagnostic imaging* / Q000502:physiology; D016477:Artifacts; D001783:Blood Flow Velocity; D002339:Carotid Arteries / Q000000981:diagnostic imaging; D006801:Humans; D012189:Retrospective Studies; D013348:Subclavian Artery / Q000000981:diagnostic imaging; D013350:Subclavian Vein / Q000000981:diagnostic imaging; D014463:Ultrasonography; D018615:Ultrasonography, Doppler, Color