Implantable Device MRI Detection via Magnetic Field Sensing

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Solution Overview

Problem

Implantable medical devices, such as pacemakers and defibrillators, face malfunctions when exposed to MRI devices due to induced electrical signals, necessitating reliable detection of MRI presence to modify operation and prevent errors during MRI examinations.

Innovation Solution

An implantable medical device with a sensing device that monitors magnetic field strength and a processing device that analyzes measurement values to detect a steady increase, using a counter value system to differentiate between MRI presence and other external devices, allowing operation modification to prevent malfunctions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the implantable medical device uses a sensing device to detect magnetic field changes, then the device can detect the presence of an MRI device, but the device complexity increases due to additional sensing components and processing requirements

Engineering Contradiction:
Improvedetection accuracyVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The sensing device is integrated into the implantable medical device to serve multiple functions: normal operation monitoring and MRI detection. The processing device analyzes measurement values from the sensing device to determine both operational parameters and MRI presence, allowing one component to fulfill multiple roles rather than adding separate dedicated systems.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The processing device detects MRI presence by analyzing changes in magnetic field strength parameters from the sensing device. By monitoring parameter variations (increases in magnetic field strength) rather than requiring dedicated MRI-specific hardware, the system achieves detection capability while minimizing additional complexity.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the implantable medical device modifies operation to reduce MRI risk, then the safety during MRI procedures improves, but the ease of operation decreases due to automatic mode switching

Engineering Contradiction:
Improvesafety during MRIVSAvoidease of operation
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The processing device automatically modifies the operation of the implantable medical device in advance when MRI presence is detected, switching to a safe mode before potential harm can occur. This preliminary protective action eliminates the need for manual intervention during the critical MRI detection and response sequence.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The processing device continuously monitors measurement values from the sensing device and automatically adjusts operation based on detected magnetic field changes. This feedback mechanism enables the device to self-regulate its operation in response to MRI presence, removing the burden of manual control from the user.

Inventive Principle:
Principle #23Feedback

3Measurement precision

If the device analyzes multiple measurement values to detect steady increase in magnetic field strength, then the measurement precision improves for distinguishing MRI from other devices, but the loss of time increases due to multiple measurements and analysis

Engineering Contradiction:
Improvedetection accuracyVSAvoiddetection time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The processing device analyzes a multiplicity of measurement values to detect steady increases in magnetic field strength, using more measurements than the absolute minimum required. This excessive action approach ensures accurate differentiation between MRI devices and other external devices by looking for the characteristic steady increase pattern, even though it requires multiple sequential measurements.

Inventive Principle:
Principle #16Partial or excessive action

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

Effectively detects the presence of an MRI device by analyzing magnetic field strength changes, enabling the implantable medical device to switch to a safe mode, reducing the risk of erroneous stimulation or shocks during MRI procedures.

Implementation Method 1

The implantable medical device comprises a sensing device for sensing a magnetic field

Methodology Applied
Scientific EffectMagnetic field sensing: Magnetic Field

Data Source

PatentEP4106861B1Implantable medical device configured for detecting a presence of an MRI device
Publication Date: 2024.12.11 BIOTRONIK SE & CO KG
  • EP4106861B1 patent drawingFigure 1
  • EP4106861B1 patent drawingFigure 2~3
  • EP4106861B1 patent drawingFigure 4

AI summary

An implantable medical device (1) comprises a sensing device (103) for sensing a magnetic field (M), and a processing device (101) configured to detect a presence of an MRI device (3) based on measurement values (S) obtained from the sensing device (103). The processing device (101) is configured to conclude that an MRI device (3) is present if a multiplicity of measurement values (S) indicates an increase of a strength of the magnetic field (M). Further, the sensing device (103) is configured to conduct measurements at a specified frequency in between 1 Hz and 50 Hz, in particular at 4 Hz, and to provide measurement values (S) at a predefined sampling rate.