A new CT artefact - the bubble curve sign.

Since the introduction of the original single-section computed tomography (CT) machines, and more recent spiral CT, several different types of CT artefact have been described. Recognized artefacts include motion artefact, metallic streak artefact, beam hardening, partial volume artefact and step artefact. The use of contrast-enhanced spiral CT has created many new artefacts and potential pitfalls. 4 Herts B.R. Einstein D.M. Paushter D.M. Spiral CT of the abdomen: artifacts and potential pitfalls. AJR Am J Roentgenol. 1993; 161: 1185-1190 Crossref PubMed Scopus (52) Google Scholar Imaging too early, or in a patient with poor cardiac output leads to heterogeneous appearances of the spleen and liver. Mixing of unopacified venous blood from the legs with opacified renal venous blood in the inferior vena cava (IVC) gives the false impression of thrombus. Artefacts are also prevalent in multi-detector CT coronary angiography 5 Choi H.S. Choi B.W. Choe K.O. et al. Pitfalls, artifacts, and remedies in multi– detector row CT coronary angiography. RadioGraphics. 2004; 24: 787-800 Crossref PubMed Scopus (103) Google Scholar and motion artefact can cause the appearance of an anomalous right coronary artery. 6 Katoh M. Wildberger J.E. Gunther R.W. et al. Malignant right coronary artery anomaly simulated by motion artifacts on MDCT. AJR Am J Roentgenol. 2005; 185: 1007-1010 Crossref PubMed Scopus (12) Google Scholar Much research has been carried out to both understand and reduce these artifacts. 7 Kyriakou Y. Kachelrieβ M. Knaup M. et al. Impact of the z-flying spot on resolution and artifact behaviour for a 64-slice spiral CT scanner. Eur Radiol. 2006; 16: 1206-1215 Crossref PubMed Scopus (36) Google Scholar , 8 Hseih J. Analytical models for multi-slice helical CT performance parameters. Med Phys. 2003; 30: 169-178 Crossref PubMed Scopus (37) Google Scholar , 9 Schardt P. Deuringer J. Freudenberger J. et al. New x-ray tube performance in computed tomography by introducing the rotating envelope tube. Med Phys. 2004; 32: 2699-2706 Crossref Scopus (81) Google Scholar , 10 Taguchi K. Aradate H. Saito Y. The cause of the artifact in 4-slice helical computed tomography. Med Phys. 2004; 31: 2033-2037 Crossref PubMed Scopus (11) Google Scholar