title: Photoelastic stress analysis in blood vessel phantoms: three-dimensional visualization and saccular aneurysm with bleb.
abstract: BACKGROUND
  The photoelastic effect is used for stress measurement during endovascular surgery simulation for quantitative evaluation of catheter trajectory in in vitro environments. By extending the capabilities of this sensing technology, its potential for intravascular tools evaluation will increase.
  
  
  METHODS
  In this research the error introduced by stress direction on magnitude measurements was studied, then stress measurements were made in the phantom modelling of a saccular aneurysm with bleb. To visualize three-dimensionally the stress field changes produced by a guide wire in a phantom wall, a scanner and an algorithm relying on maximum likelihood-expectation maximization are proposed. Three-dimensional fields at different pressure level were compared with the stress field surrounding the guide wire.
  
  
  RESULTS
  The maximum error in stress magnitude measurements due to stress direction was 2.52%. Stress local maximum was detected in the bleb phantom before rupture. Three-dimensional visualization was obtained in vasculature phantom with average errors of 10.73%, 4.55%, 3.18% for inner pressures of 80, 120, 160 mmHg, respectively. Stress measurement in the neighbourhood of the guide wire is equivalent to applying an inner pressure of 120 mmHg.
  
  
  CONCLUSIONS
  For the presented polariscope, the weak influence of stress direction in magnitude measurements was confirmed. In vasculature phantoms, the three-dimensional visualization of stress eliminated birefringence visualization distortion and enabled more comprehensive comparison of stress produced by intravascular tools with stress produced by normal blood pressure.
authors.affiliation: Department of Micro-Nano Systems Engineering, Nagoya University, Nagoya, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Matsushima
authors.forename: C
authors.initials: C
authors.lastname: Tercero
authors.forename: S
authors.initials: S
authors.lastname: Ikeda
authors.forename: T
authors.initials: T
authors.lastname: Fukuda
authors.forename: F
authors.initials: F
authors.lastname: Arai
authors.forename: M
authors.initials: M
authors.lastname: Negoro
authors.forename: I
authors.initials: I
authors.lastname: Takahashi
mesh_terms: D000783:Aneurysm / Q000473:pathology* / Q000503:physiopathology*; D003198:Computer Simulation; D055119:Elastic Modulus; D004724:Endoscopy / Q000379:methods*; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008955:Models, Cardiovascular; D019047:Phantoms, Imaging; D012031:Refractometry / Q000379:methods*; D033081:Shear Strength; D013314:Stress, Mechanical