A novel method for measuring the torque on implantable cardiovascular devices in MR static fields
✍ Scribed by Giuseppe D'Avenio; Rossella Canese; Franca Podo; Mauro Grigioni
- Publisher
- John Wiley and Sons
- Year
- 2007
- Tongue
- English
- Weight
- 337 KB
- Volume
- 26
- Category
- Article
- ISSN
- 1053-1807
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✦ Synopsis
Abstract
Purpose
To propose a novel quantitative method for measuring the torque acting on mechanical heart valve prostheses subjected to a high static magnetic field in a MR scanner.
Materials and Methods
Torque measurements were performed with a torsion balance, implemented with a copper wire. The reaction torque exerted by the static magnetic field on the device was measured optically from the deflection angle of a laser beam spot on a graduate scale. Three different types of mechanical valves (two bileaflet and one monoleaflet) were tested at different locations of a small bore 4.7 tesla system.
Results
The method proved to be particularly sensitive (detectability limit lower than 10^−6^ N · m), reliable and yielded quantitative reproducible results. The equivalent force of the torque measured for the three valves was at least 10^3^‐fold lower than the force exerted by the beating heart.
Conclusion
The proposed method provides a quantitative evaluation of the torque induced on prosthetic device by a MR scanner operating at high magnetic field. J. Magn. Reson. Imaging 2007;26:1368–1374. © 2007 Wiley‐Liss, Inc.