title: In vitro stent assessment by MRI: visibility of lumen and artifacts for 27 modern stents.
abstract: OBJECTIVE
  The purpose of this study was to measure artifacts and visibility of lumen for modern and most commonly used stents in vascular interventions according to a standardized test method of the American Society for Testing and Materials (ASTM).
  
  
  METHODS
  Twenty-four peripheral self-expanding nitinol stents and three stainless steel stents with diameters between 5 and 8 mm and lengths between 30 and 250 mm from seven different manufacturers were compared on a 1.5T and a 3T magnetic resonance (MR) scanner. The visualization of lumen and artifacts was measured according to ASTM F2119 for a turbo spin echo (TSE) [repetition time(TR)/echo time (TE) 500/26 ms] and a gradient echo (GRE) (TR/TE 100/15 ms) sequence. The stents were placed parallel and perpendicular to the radio frequency field (B1).
  
  
  RESULTS
  There were large differences in visibility of the lumen for the stent models. The visualization of the lumen varies between 0% and 93% (perpendicular to B1), and 0% and 78% (parallel to B1), respectively. The maximum signal loss beyond the actual diameter was 6 mm (TSE) and 10 mm (GRE) for stents made of stainless steel, and lower than 1 mm (TSE) and 4 mm (GRE) for nitinol stents.
  
  
  CONCLUSIONS
  Reliable stent lumen visualization is possible for Misago, Supera, Tigris, and Viabahn stents, if their axis is perpendicular to B1, and independent of the orientation with respect to B1 for short Tigris stents at 1.5T.
authors.affiliation: .
authors.forename: Andreas
authors.initials: A
authors.lastname: Heinrich
authors.affiliation: .
authors.forename: Felix V
authors.initials: FV
authors.lastname: Güttler
authors.affiliation: .
authors.forename: Florian
authors.initials: F
authors.lastname: Schlesies
authors.affiliation: .
authors.forename: René
authors.initials: R
authors.lastname: Aschenbach
authors.affiliation: .
authors.forename: Niklas
authors.initials: N
authors.lastname: Eckardt
authors.affiliation: .
authors.forename: Ulf K-M
authors.initials: UK
authors.lastname: Teichgräber
mesh_terms: D000497:Alloys / Q000737:chemistry*; D006801:Humans; D018810:Magnetic Resonance Angiography / Q000379:methods*; D013193:Stainless Steel; D015607:Stents
chemical_list: D000497:Alloys; D013193:Stainless Steel; C013616:nitinol
keywords: artifacts; diagnostic; magnetic resonance imaging; stenosis; stent graft