title: In-vitro imaging of femoral artery nitinol stents for deformation analysis.
abstract: OBJECTIVE
  Femoral artery stents are prone to fracture, and studying their deformations could lead to a better understanding of the cause of breakage. The present study sought to develop a method of imaging and analyzing stent deformation in vitro with use of a calibrated test device.
  
  
  METHODS
  High-resolution (approximately 200 μm) volumetric data were obtained with a flat-panel detector-based C-arm computed tomography system. A nitinol stent placed in a testing device was imaged with various loads that caused bending, axial tension, and torsion. Semiautomatic software was developed to calculate the bending, extension, and torsion from the stent images by measuring the changes in the radius of curvature, eccentricity, and angular distortions.
  
  
  RESULTS
  For the axial tension case, there was generally good agreement between the physical measurements and the image-based measurements. The bending measurements had better agreement at bend angles lower than 30°. For stent torsion, the hysteresis between the loading and unloading curves were larger for the image-based results compared with physical measurements.
  
  
  CONCLUSIONS
  An imaging and analysis framework has been set up for the analysis of stent deformations that shows fairly good agreement between physical and image-based measurements.
authors.affiliation: Department of Radiology, Stanford University, 1201 Welch Rd., Palo Alto, CA 94305, USA. aganguly@stanford.edu
authors.forename: Arundhuti
authors.initials: A
authors.lastname: Ganguly
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Simons
authors.forename: Alex
authors.initials: A
authors.lastname: Schneider
authors.forename: Benjamin
authors.initials: B
authors.lastname: Keck
authors.forename: Nathan R
authors.initials: NR
authors.lastname: Bennett
authors.forename: Rebecca
authors.initials: R
authors.lastname: Fahrig
mesh_terms: D000497:Alloys; D000792:Angiography / Q000379:methods*; D001807:Blood Vessel Prosthesis; D055119:Elastic Modulus; D019544:Equipment Failure Analysis / Q000379:methods; D005263:Femoral Artery / Q000000981:diagnostic imaging* / Q000601:surgery*; D006801:Humans; D011474:Prosthesis Design; D015607:Stents; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D000497:Alloys; C013616:nitinol