Uniformity of Expansion / Dog Boning Effect

Stent expansion uniformity: Difference between the largest and smallest diameter measurement on a single stent deployed to its labelled diameter.

Test Procedure

A contactless optical gauging machine (Smartscope, OGP) is used (highest magnification: x145) to assess stent expansion uniformity. Diameter is measured at 3 axial locations of the stent and 2 perpendicular circumferential orientations when the stent is deployed at his labeled diameter.

Determines the Conformability to vessel wall and investigates any potential profile effects such as flaring or Dog boning.

Measured Parameters

Difference between the largest and smallest diameter measurement on a single stent deployed to its labelled diameter


  • Balloon Expandable Stent
  • Self-expending stent
  • SS, CrCo, NiTi, any other metal alloys

Service Levels

Applicable Standards

  • ISO 25539-2:2020
    Cardiovascular implants — Endovascular devices — Part 2: Vascular stents

Related Tests


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