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Updated: Jun 14, 2026
Ferromagnetic Bare Metal Stent for Endothelial Cell Capture and Retention
Published on: September 18, 2015
Micro-CT-compatible technique for measuring self-expanding stent forces
Hristo N Nikolov1, David M Pelz, Stephen P Lownie
1Imaging Research Laboratories, Robarts Research Institute, University of Western Ontario, London, Canada. hnikolov@imaging.robarts.ca
Purpose:
To develop and evaluate a technique for measuring the radial resistive force, chronic outward force, and dimensions of self-expanding stents.
Materials And Methods:
A Mylar film was looped around the stent, threaded through two carbon fiber rods, and immersed in a 37 degrees C oil bath. A force gauge mounted on a micro-positioning stage was used to measure the applied forces. The apparatus containing the self-expanding nitinol stent (diameter, 40 mm; length, 80 mm) was placed inside a micro-computed tomographic (CT) scanner. At each stent deformation, the load was manually recorded from the force gauge and a micro-CT volume (isotropic voxel spacing, 0.15 mm) obtained. Stent diameter and length were measured from the images, and radial resistive force and chronic outward force were calculated for each deformation.
Results:
The stress-strain curves indicate that the stents exert much smaller maximum outward forces (1.2 N/cm) than the force that is required to compress them (3.6 N/cm). The forces were measured with a precision of +/-3.3% (standard deviation of five repeated measurements). The stent's diameter was measured with precision better than 0.3% and accuracy of +/-0.1 mm.
Conclusions:
The authors have developed a radiographic technique that enables precise measurements of radial resistive force, chronic outward force, and the dimensions of self-expanding stents during deformation.
