An RF-induced voltage sensor for investigating pacemaker safety in MRI.

Area of Science:

• Biomedical Engineering
• Medical Imaging Physics

Background:

• Magnetic resonance imaging (MRI) poses risks for patients with pacemakers due to potential radiofrequency (RF) induced voltages in leads.
• Malfunction of pacemakers during MRI can lead to serious health complications.

Purpose of the Study:

• To develop and validate a novel sensor for measuring RF-induced voltages in pacemaker leads during MRI procedures.
• To enhance the safety protocols for pacemaker patients undergoing MRI scans.

Main Methods:

• A specialized sensor (16.6 cm(2)) was designed to measure voltages at the pacemaker lead-case connection.
• The sensor utilizes demodulation, digitization, and optical fiber transfer for induced voltage measurement.
• Calibration was performed on a benchtop, followed by testing in a 1.5 T MRI scanner using a saline phantom.

Main Results:

• Bench calibration demonstrated measurement errors below 5% within a -40 V to +40 V range, with 0.06 V precision and 24.2 μs temporal resolution.
• MRI tests showed less than 3.7% variability across 996 measurements, indicating high reproducibility.
• Sensor coupling to the MRI environment was below 6.2%, and typical clinical MRI sequences induced approximately ten Vp.

Conclusions:

• An accurate and reproducible sensor tool was developed for measuring RF-induced voltages in pacemaker leads during MRI safety assessments.
• The sensor technology shows potential for use with other conducting cables, such as those in electrocardiography and neurostimulation.