Micro-CT–compatible Technique for Measuring Self-expanding Stent Forces

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°C oil bath. A force gauge...

Full description

Saved in:
Bibliographic Details
Published inJournal of vascular and interventional radiology Vol. 21; no. 4; pp. 562 - 570
Main Authors Nikolov, Hristo N., MSc, Pelz, David M., MD, Lownie, Stephen P., MD, Norley, Chris J.D., BSc, Khan, Vajid, MD, Drangova, Maria, PhD, Holdsworth, David W., PhD
Format Journal Article
LanguageEnglish
Published United States Elsevier Inc 01.04.2010
Subjects
Online AccessGet full text

Cover

Loading…
More Information
Summary: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°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.
Bibliography:ObjectType-Article-1
SourceType-Scholarly Journals-1
ObjectType-Feature-2
content type line 23
ISSN:1051-0443
1535-7732
DOI:10.1016/j.jvir.2010.01.016