title: Coronary magnetic resonance angiography for assessment of the stent lumen: a phantom study.
abstract: OBJECTIVE
  To evaluate the feasibility of visualizing the stent lumen using coronary magnetic resonance angiography in vitro.
  
  
  METHODS
  Nineteen different coronary stents were implanted in plastic tubes with an inner diameter of 3 mm. The tubes were positioned in a plastic container filled with gel and included in a closed flow circuit (constant flow 18 cm/sec). The magnetic resonance images were obtained with a dual inversion fast spin-echo sequence. For intraluminal stent imaging, subtraction images were calculated from scans with and without flow. Subsequently, intraluminal signal properties were objectively assessed and compared.
  
  
  RESULTS
  As a function of the stent type, various degrees of in-stent signal attenuation were observed. Tantalum stents demonstrated minimal intraluminal signal attenuation. For nitinol stents, the stent lumen could be identified, but the intraluminal signal was markedly reduced. Steel stents resulted in the most pronounced intraluminal signal voids.
  
  
  CONCLUSIONS
  With the present technique, radiofrequency penetration into the stents is strongly influenced by the stent material. Thesefindings may have important implicationsforfuture stent design and stent imaging strategies.
authors.affiliation: Department of Cardiology and Radiology, Leiden University Medical Center, The Netherlands. maintz@uni-muenster.de
authors.forename: David
authors.initials: D
authors.lastname: Maintz
authors.forename: Rene M
authors.initials: RM
authors.lastname: Botnar
authors.forename: Roman
authors.initials: R
authors.lastname: Fischbach
authors.forename: Walter
authors.initials: W
authors.lastname: Heindel
authors.forename: Warren J
authors.initials: WJ
authors.lastname: Manning
authors.forename: Matthias
authors.initials: M
authors.lastname: Stuber
mesh_terms: D019917:Blood Vessel Prosthesis Implantation; D017023:Coronary Angiography / Q000295:instrumentation*; D003324:Coronary Artery Disease / Q000175:diagnosis / Q000601:surgery; D003331:Coronary Vessels / Q000601:surgery*; D004867:Equipment Design / Q000295:instrumentation; D005240:Feasibility Studies; D006801:Humans; D018810:Magnetic Resonance Angiography / Q000295:instrumentation*; D019047:Phantoms, Imaging; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation; D015607:Stents