Segmented Electrode Capacitor for MRI Safety in Implantable Devices

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Solution Overview

Problem

Implantable medical devices (IMDs) face safety concerns in MRI environments due to adverse reactions such as heating, vibration, and induced voltages caused by magnetic fields, particularly affecting capacitors within these devices.

Innovation Solution

The design of segmented electrodes for capacitors in IMDs, which reduces the surface area of the electrodes to minimize the size of eddy current loops, thereby decreasing the response to MRI magnetic fields, making the devices MRI Safe by minimizing heating and movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional capacitor electrodes are used in IMDs, then the device can perform its medical function, but the device poses safety hazards in MRI environments due to eddy current heating and induced voltages

Engineering Contradiction:
ImproveMRI safetyVSAvoideddy current heating and induced voltages
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The capacitor electrodes are segmented into multiple separate conductive regions rather than using continuous traditional electrodes. This segmentation breaks up the eddy current paths, reducing the loop area and thereby minimizing induced voltages and heating effects during MRI procedures while maintaining the capacitor's electrical function

Inventive Principle:
Principle #1Segmentation

2Reliability

If the surface area of capacitor electrodes is reduced to minimize eddy current loops, then MRI safety is improved, but the capacitor's electrical performance may be compromised

Engineering Contradiction:
ImproveMRI safetyVSAvoidcapacitor electrical performance
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The capacitor design implements local quality by creating regions of different electrical properties within the electrode structure. The segmented electrodes have varying conductive path lengths and cross-sectional areas in different locations, allowing optimization of both MRI safety (reduced eddy currents) and electrical performance (maintained capacitance) in their respective regions

Inventive Principle:
Principle #3Local quality

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 segmentation of electrodes in IMD capacitors effectively reduces the response to MRI environments, ensuring the safety of patients with implanted devices by minimizing heating and vibration, thus enhancing the safety of IMDs during MRI procedures.

Implementation Method 1

the design of segmented electrodes for capacitors in IMDs, which reduces the surface area of the electrodes to minimize the size of eddy current loops, thereby decreasing the response to MRI magnetic fields, making the devices MRI Safe by minimizing heating and movement

Methodology Applied
Scientific EffectEddy current: Eddy Currents

Data Source

PatentEP3078396B1Implantable device including eddy current reducing capacitor
Publication Date: 2020.04.29 CARDIAC PACEMAKERS INC
  • EP3078396B1 patent drawingFigure 1~2
  • EP3078396B1 patent drawingFigure 3~4
  • EP3078396B1 patent drawingFigure 5~6

AI summary

An implantable device, such as a pacer, defibrillator, or other cardiac rhythm management device, can include one or more MRI Safe components. In an example, the implantable device includes a capacitor including a first electrode including a first slot extending from a perimeter of the first electrode to an interior of the first electrode. A second electrode is separated from the first electrode by a first distance. The second electrode includes a second slot extending from a perimeter of the second electrode to an interior of the second electrode. The first and second slots are configured to at least partially segment surface areas of the first and second electrodes, respectively, to reduce a radial current loop size in each of the first and second electrodes.