Conductive Ink EEG Sensor System for MRI Signal Recording
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Solution Overview
Problem
Current methods for recording electrophysiological brain signals during MRI face challenges such as interference from metallic electrodes, high Specific Absorption Rate (SAR) exposure, and motion noise, which compromise signal quality and patient safety.
Innovation Solution
A conductive ink sensor system with non-ferromagnetic electrodes and leads, integrated with motion sensors, is used to reduce SAR exposure and artifact noise, featuring a multi-layered design with variable impedance and optimized layout for improved signal quality and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If metallic electrodes and leads are used for EEG recording during MRI, then electrical signal conductivity is improved, but Specific Absorption Rate (SAR) exposure and temperature increase worsen
Solution Approach 1:
The patent changes the electrical parameters of the electrodes by using conductive ink with variable impedance instead of traditional metallic electrodes. The conductive ink electrodes have lower electrical conductivity than metals, which reduces SAR exposure and temperature increase during MRI while still maintaining sufficient conductivity for EEG signal recording.
Solution Approach 2:
The patent uses composite material structure where conductive ink is applied on a flexible substrate to create electrodes that combine electrical conductivity with MRI compatibility. The conductive ink layer provides necessary electrical properties while the overall composite structure minimizes interaction with MRI radiofrequency fields, reducing harmful SAR effects.
2Speed
If conventional EEG leads are placed inside MRI scanner, then temporal resolution of brain activity recording is improved, but signal quality worsens due to artifact noise
Solution Approach 1:
The patent extracts the EEG recording system from the traditional metal-based configuration and removes the harmful metallic components that generate artifacts. By using non-metallic conductive ink electrodes and leads, the system eliminates the primary source of electromagnetic interference and artifact noise while preserving the ability to record brain activity with high temporal resolution.
Solution Approach 2:
The conductive ink acts as an intermediary material between the scalp and the recording system. This intermediate layer provides electrical contact for signal acquisition while having different electromagnetic properties than traditional metals, thereby mediating the interaction between the EEG system and MRI fields to reduce artifact generation.
3Measurement precision
If motion sensors are integrated into the electrode system, then motion artifact detection is improved, but device complexity worsens
Solution Approach 1:
The patent merges the EEG electrode function with motion sensing capability into a single integrated system. Motion sensors are incorporated into the electrode structure itself, allowing simultaneous measurement of brain electrical activity and head motion. This combination enables real-time detection and correction of motion artifacts without requiring separate monitoring equipment.
Solution Approach 2:
The electrode system is designed with multi-functionality, serving both as an electrical contact for EEG signal acquisition and as a platform for motion detection. This universal design allows the same device component to perform multiple functions, reducing the need for additional separate systems and simplifying the overall experimental setup.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively reduces SAR exposure, minimizes temperature increase, and enhances signal-to-noise ratio, allowing safe and high-quality EEG recordings in high magnetic fields while ensuring patient safety.
Implementation Method 1
interference from metallic electrodes, high Specific Absorption Rate (SAR) exposure
Implementation Method 2
integrated with motion sensors, is used to reduce SAR exposure and artifact noise
Implementation Method 3
apparatuses and methods for the delivery and recording of electrophysiological brain signals during MRI using a variable impedance electrode arrangement
Data Source
AI summary
Methods, systems and arrangements are provided for obtaining electroencephalograph (“EEG”) EEG signals from a patient e.g., during a concurrent EEG/MRI examination of the patient. The methods, systems and arrangements include a cap made of conductive inks with sensor positions for attaching a plurality of sensors to the patient's head. The sensors can include electrodes as well as motion sensors for improving EEG signal quality and MRI image quality in the presence of motion noise and other artifacts within the MRI environment. The electrodes may be composed of conductive inks, and can be used in high magnetic fields due to a weak interaction with the RF fields generated by the MRI scanner. The exemplary methods, systems and arrangements can achieve lower SAR and lower temperature increase, as compared to conventional electrodes.