A novel method for measuring the torque on implantable cardiovascular devices in MR static fields

Area of Science:

• Biomedical Engineering
• Medical Imaging Physics

Background:

• Mechanical heart valves are crucial implants.
• Magnetic Resonance (MR) imaging uses strong magnetic fields.
• Assessing device safety in MR environments is critical.

Purpose of the Study:

• To introduce a novel quantitative method for measuring torque on mechanical heart valve prostheses.
• To evaluate torque forces exerted by high static magnetic fields in MR scanners.

Main Methods:

• A torsion balance with a copper wire was employed for torque measurements.
• Optical detection of laser beam deflection quantified reaction torque.
• Three mechanical heart valve types were tested in a 4.7 tesla MR system.

Main Results:

• The method demonstrated high sensitivity (detectability limit < 10(-6) N x m).
• Quantitative and reproducible results were obtained.
• Measured torque forces were at least 1000-fold lower than cardiac forces.

Conclusions:

• The developed method enables quantitative assessment of MR-induced torque on prosthetic devices.
• Findings suggest mechanical heart valves are safe concerning magnetic torque in high-field MR scanners.