title: MR-velocity mapping in vascular stents to assess peak systolic velocity. In vitro comparison of various stent designs made of Stainless Steel and Nitinol.
abstract: BACKGROUND
  Peak systolic velocity (PSV) measurements of blood flow inside vascular stents allow reliable detection of in-stent re-stenosis. The purpose of this in vitro study was to evaluate the feasibility of obtaining PSV measurements inside vascular stents made of Stainless Steel and Nitinol, using a velocity encoded MR technique.
  
  
  METHODS
  In a flow phantom, stents of Stainless Steel and Nitinol were studied. The phantom was integrated into a closed-tubing circuit driven by a MR dedicated pulsatile flow pump. MR imaging was performed on a 1.5 T system. The PSV in the tube without stent was used as the gold standard to determine the accuracy and the variability (paired t-test and Pittman's test) of the PSV measurements inside the stents.
  
  
  RESULTS
  PSV values inside the stents showed percentual difference in mean of -15 to 21% (P < 0.05) at a pump setting of 10 and 20 ml/s.
  
  
  CONCLUSIONS
  PSV measurements can be accurately obtained inside stents made of Stainless Steel and Nitinol. MR-velocity measurements may be used in patients to non-invasively evaluate stent patency and in-stent re-stenosis.
authors.affiliation: Department of Radiology, Erasmus MC, University Medical Center Rotterdam, Dr Molewaterplein 40, 3015GD Rotterdam, The Netherlands. vanholten@rond.azr.nl
authors.forename: Jacqueline
authors.initials: J
authors.lastname: van Holten
authors.forename: Patrik
authors.initials: P
authors.lastname: Kunz
authors.forename: Paul G H
authors.initials: PG
authors.lastname: Mulder
authors.forename: Peter M T
authors.initials: PM
authors.lastname: Pattynama
authors.forename: Hildo J
authors.initials: HJ
authors.lastname: Lamb
authors.forename: Lukas C
authors.initials: LC
authors.lastname: van Dijk
mesh_terms: D000497:Alloys; D001158:Arteries / Q000503:physiopathology* / Q000601:surgery*; D001783:Blood Flow Velocity; D019544:Equipment Failure Analysis / Q000295:instrumentation / Q000379:methods*; D005240:Feasibility Studies; D006801:Humans; D018810:Magnetic Resonance Angiography / Q000295:instrumentation / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods*; D019028:Magnetic Resonance Imaging, Cine / Q000295:instrumentation / Q000379:methods; D019047:Phantoms, Imaging; D012016:Reference Values; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013193:Stainless Steel; D015607:Stents; D013599:Systole
chemical_list: D000497:Alloys; D013193:Stainless Steel; C013616:nitinol