Fiber-Optic ECG Measurement Node for MRI Noise and RF Heating

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional ECG systems face challenges in an MRI environment due to signal degradation from MRI noise pickup and RF heating, and interference with MRI image quality, especially with galvanic ECG lead connections.

Innovation Solution

A system utilizing voltage-to-frequency converters, optical converters, and DC power converters connected to a virtual ground, eliminating the need for conductive leads by transmitting ECG signals optically through fiber-optic cables.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If galvanic ECG lead connections are used to transmit ECG signals from electrodes to processing module, then ECG signal transmission is achieved, but signal degradation occurs due to MRI noise pickup and RF heating

Engineering Contradiction:

ImproveECG signal qualityVSAvoidMRI noise pickup and RF heating

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces fiber-optic cables as an intermediary medium to transmit ECG signals. The optical converter at each electrode converts electrical ECG signals to optical signals, which are then transmitted through fiber-optic cables to the processing module. This intermediary optical transmission system isolates the ECG measurement circuitry from MRI electromagnetic interference and RF heating effects, eliminating signal degradation while maintaining reliable signal transmission.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the conventional galvanic (electrical) lead connection system with an optical transmission system. Instead of using electrical wires that are susceptible to MRI interference and RF heating, the system uses optical converters and fiber-optic cables to transmit signals. This substitution eliminates the harmful interactions with MRI fields while preserving the ECG signal transmission function.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If ECG leads are placed inside MRI bore to enable real-time monitoring, then ECG pulse acquisition is achieved, but interference with MRI image quality occurs

Engineering Contradiction:

ImproveReal-time ECG monitoring capabilityVSAvoidMRI image quality interference

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent uses fiber-optic cables as intermediaries to transmit ECG signals from electrodes placed on the patient inside the MRI bore to processing equipment outside the bore. Since fiber-optic cables are non-conductive and immune to electromagnetic interference, they do not interfere with MRI image quality while enabling continuous real-time ECG monitoring during the MRI procedure.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If conventional ECG leads are used in MRI environment, then ECG signal transmission is achieved, but thermal injuries may occur due to RF heating

Engineering Contradiction:

ImproveECG signal transmissionVSAvoidRF heating causing thermal injuries

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

The patent replaces electrical ECG leads with an optical transmission system consisting of optical converters and fiber-optic cables. This substitution eliminates the conductive pathways that would otherwise be susceptible to RF heating in the MRI environment, thereby preventing thermal injuries to sedated patients while maintaining ECG signal transmission capability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

Reduces signal degradation and RF heating, while maintaining MRI image quality by using a virtual ground and optical signal transmission, ensuring reliable ECG pulse acquisition during MRI procedures.

Implementation Method 1

a voltage-to-frequency converter (VFC) configured to convert an ECG signal from the corresponding ECG electrode to a frequency signal

Methodology Applied

Scientific EffectVoltage-to-frequency conversion:

Implementation Method 2

an optical converter configured to convert the frequency signal from the VFC to an optical signal, and to output the optical signal via an output fiber-optic cable

Methodology Applied

Scientific EffectOptical conversion:

Implementation Method 3

a DC power converter configured to receive a modulated optical signal via an input fiber-optic cable, to recover DC power from the modulated optical signal, and to supply the DC power to at least the VFC and the optical converter

Methodology Applied

Scientific EffectOptical power recovery: Photovoltaic Effect

Data Source

PatentUS20250366755A1Voltage-to-frquency electrocariogram measurement node

Publication Date: 2025.12.04 KONINKLIJKE PHILIPS NV

AI summary

A system for acquiring electrocardiogram (ECG) pulses from a subject, comprising: a virtual ground; and a plurality of measurement nodes connectable to a plurality of corresponding ECG electrodes, wherein the plurality of measurement nodes are connected to the virtual ground, and wherein each measurement node comprises: a voltage-to-frequency converter (VFC) configured to convert an ECG signal from the corresponding ECG electrode to a frequency signal; an optical converter configured to convert the frequency signal from the VFC to an optical signal, and to output the optical signal via an output fiber-optic cable; and a DC power converter configured to receive a modulated optical signal via an input fiber-optic cable, to recover DC power from the modulated optical signal, and to supply the DC power to at least the VFC and the optical converter.