title: Contrast-enhanced MR angiography at 1.5 T after implantation of platinum stents: in vitro and in vivo comparison with conventional stent designs.
abstract: OBJECTIVE
  The objective of our study was to evaluate the in vitro and in vivo 3D contrast-enhanced MR angiography characteristics of a new platinum-based balloon-expandable stent system and compare this system with a variety of competing metallic stents.
  
  
  METHODS
  All experiments were performed on 1.5-T scanners. In vitro experiments were performed using 10 stents implanted into a custom-built phantom. Different orientations of the stents along the magnetic field and multiple flip angles were examined. In addition, 19 patients underwent contrast-enhanced MR angiography after the implantation of 36 stents, including four patients with six platinum stents. Angiographic correlation was available for all 19 patients, and luminal patency and stent-induced artifacts were assessed quantitatively.
  
  
  RESULTS
  Of the tested balloon-expandable stents, only the platinum-based stents created artifact causing luminal narrowing of 30% or less. All other balloon-expandable stents induced larger artifacts that resulted in higher degrees of narrowing. Thus, if patent, the platinum-based stents allow significant in-stent stenosis to be ruled out reliably. Selected nitinol- or tantalum-based self-expandable stents also are suitable in this regard.
  
  
  CONCLUSIONS
  Of the tested devices, platinum-based stents are the only type of currently available balloon-expandable stent that creates 30% or less artifact-induced apparent stenosis and thus are suitable for MR angiography.
authors.affiliation: Department of Radiology, Division of Interventional Radiology, University of Virginia Health System, Box 800170, Charlottesville, VA 22908, USA.
authors.forename: Klaus D
authors.initials: KD
authors.lastname: Hagspiel
authors.forename: D A
authors.initials: DA
authors.lastname: Leung
authors.forename: Kiran R
authors.initials: KR
authors.lastname: Nandalur
authors.forename: John F
authors.initials: JF
authors.lastname: Angle
authors.forename: Harjot S
authors.initials: HS
authors.lastname: Dulai
authors.forename: David J
authors.initials: DJ
authors.lastname: Spinosa
authors.forename: A H
authors.initials: AH
authors.lastname: Matsumoto
authors.forename: J M
authors.initials: JM
authors.lastname: Christopher
authors.forename: Hossam
authors.initials: H
authors.lastname: Ahmed
authors.forename: S S
authors.initials: SS
authors.lastname: Berr
mesh_terms: D000368:Aged; D000792:Angiography; D001157:Arterial Occlusive Diseases / Q000628:therapy*; D016477:Artifacts; D003287:Contrast Media; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D066298:In Vitro Techniques; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D019047:Phantoms, Imaging; D010984:Platinum; D012189:Retrospective Studies; D015607:Stents; D014654:Vascular Patency
chemical_list: D003287:Contrast Media; D010984:Platinum; C064925:gadodiamide; D019786:Gadolinium DTPA