title: Three-dimensional MR angiography in imaging platinum alloy stents.
abstract: OBJECTIVE
  To evaluate visualization inside platinum stents with three-dimensional contrast-enhanced magnetic resonance angiography (CE-MRA).
  
  
  METHODS
  Breath-hold three-dimensional gadolinium (Gd) MRA was performed on 18 patients with 22 platinum stents in the renal (n = 18), celiac (n = 1), superior mesenteric (n = 1), and iliac (n = 2) arteries. Electronic calibers were used to measure the lumen diameter within the stent and just distal to the stent to calculate percent stenosis. MRA accuracy was determined from the difference between percent stenosis measured on MRA and digital subtracted angiography (DSA). The patients were imaged at flip angles of 45 degrees , 60 degrees , 75 degrees , 90 degrees , and 150 degrees .
  
  
  RESULTS
  MRA demonstrated the stent lumen in all of the patients, with a mean difference between MRA and DSA of 21%. For stents oriented parallel to B0 (iliac arteries) the difference was only 10%, as compared to 22% for stents perpendicular to B0. The flip angle with the best agreement between MRA and DSA was 75 degrees (16%).
  
  
  CONCLUSIONS
  The lumen of a platinum stent can be imaged with three-dimensional CE-MRA, although grading of restenosis has limited accuracy. The best results were obtained with a flip angle of 75 degrees and for stents in the iliac arteries parallel to B0.
authors.affiliation: Department of Radiology, Weill Cornell Medical College, New York, New York 10022, USA.
authors.forename: David W
authors.initials: DW
authors.lastname: Trost
authors.forename: Hong Lei
authors.initials: HL
authors.lastname: Zhang
authors.forename: Martin R
authors.initials: MR
authors.lastname: Prince
authors.forename: Priscilla A
authors.initials: PA
authors.lastname: Winchester
authors.forename: Yi
authors.initials: Y
authors.lastname: Wang
authors.forename: Richard
authors.initials: R
authors.lastname: Watts
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Sos
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015901:Angiography, Digital Subtraction; D002445:Celiac Artery / Q000000981:diagnostic imaging / Q000473:pathology; D003250:Constriction; D003287:Contrast Media; D003974:Diatrizoate Meglumine; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D007083:Iliac Artery / Q000000981:diagnostic imaging / Q000473:pathology; D021621:Imaging, Three-Dimensional; D018810:Magnetic Resonance Angiography; D008297:Male; D017538:Mesenteric Artery, Superior / Q000000981:diagnostic imaging / Q000473:pathology; D008875:Middle Aged; D010984:Platinum; D012077:Renal Artery / Q000000981:diagnostic imaging / Q000473:pathology; D015607:Stents
chemical_list: D003287:Contrast Media; D003974:Diatrizoate Meglumine; D010984:Platinum; D019786:Gadolinium DTPA