An experimental setup to characterize MR switched gradient-induced potentials

Area of Science:

• Biomedical Engineering
• Medical Imaging Physics
• Neuroscience Instrumentation

Background:

• Electrophysiological signals (EPS) are susceptible to contamination from the strong electromagnetic fields present in Magnetic Resonance Imaging (MRI) environments.
• Switching gradient fields in MRI sequences can induce potentials that interfere with the accurate measurement of bio-potentials.
• Developing robust methods to study and mitigate MRI-induced noise is crucial for multimodal imaging research.

Purpose of the Study:

• To develop and validate an in vitro experimental setup for investigating MRI-induced contamination of electrophysiological signals (EPS).
• To characterize the switched gradient-induced potentials within an MRI environment.
• To analyze the impact of slice orientation on induced potentials during MRI acquisition.

Main Methods:

• An MRI-compatible experimental setup was designed, including signal transmission, a tissue-mimicking phantom, and an on-site detection module with pre-amplification and optical fiber transmission.
• A multi-channel receiver with selectable low-pass filters (350 Hz, 160 Hz, 80 Hz, 40 Hz) was used for signal reception in the control room.
• Signal processing algorithms were employed to analyze the induced potentials, with specific tests focusing on varying slice orientations (axial, coronal, sagittal) within a defined MRI sequence.

Main Results:

• The electronic performance of the developed setup was validated through a series of tests.
• Significant modifications in the time and frequency characteristics of the induced potentials were observed.
• These modifications were found to be dependent on the slice orientation (axial, coronal, sagittal) relative to the MRI sequence.

Conclusions:

• The developed experimental setup serves as a valuable in vitro research tool for studying MRI-induced noise in electrophysiological signals.
• The findings demonstrate that MRI slice orientation significantly influences the characteristics of induced potentials.
• This research provides insights into mitigating MRI contamination for combined electrophysiology and imaging studies.