Implantable Lead Extension Layout for MRI Heating Reduction
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Solution Overview
Problem
Existing implantable medical device leads, such as those used in neuro-stimulators, experience heating and damage during magnetic resonance imaging (MRI) due to electromagnetic fields, leading to tissue burns and system damage.
Innovation Solution
The design incorporates an elongated, biocompatible, electrically non-conductive body with conductive filaments that extend beyond the most distal electrode, shifting the reflection point of electromagnetic waves away from the electrode tip, thereby reducing heat generation and electromagnetic interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional lead design with conductive wires is used, then electrical signal conduction is achieved, but heating and tissue damage occur during MRI due to electromagnetic field exposure
Solution Approach 1:
The patent extracts the harmful conductive function from the lead body by replacing traditional conductive wires with an electrically non-conductive body. The electrical connection is achieved through capacitive coupling between conductive elements embedded in the non-conductive body, effectively removing the direct conductive path that causes heating during MRI while maintaining necessary electrical functionality.
Solution Approach 2:
The patent changes the electrical parameter of the lead body from conductive to electrically non-conductive. This fundamental parameter change eliminates the harmful current flow during MRI exposure. The conductive elements are isolated within the non-conductive body, transforming the lead from a current-carrying conductor to a capacitive coupling structure that does not generate harmful heat during electromagnetic exposure.
2Reliability
If conductive wires are used to connect electrical connectors to electrodes, then electrical connectivity is achieved, but electromagnetic interference and heat generation occur during imaging
Solution Approach 1:
The patent introduces an electrically non-conductive body as an intermediary medium between the conductive elements (electrical connectors and electrodes). This intermediary enables electrical connectivity through capacitive coupling without direct conductive contact, thereby eliminating the electromagnetic interference and heat generation that would occur with traditional wire connections during MRI imaging.
3Ease of manufacture
If traditional lead structure is used, then simple construction is maintained, but heating during MRI causes tissue burns and system damage
Solution Approach 1:
The patent employs a composite structure combining conductive elements with an electrically non-conductive body. This composite design integrates the electrical connectivity function of conductors with the safety benefits of non-conductive materials, creating a lead that maintains manufacturability while eliminating tissue burns and system damage during MRI through the inherent properties of the non-conductive body.
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
This configuration significantly reduces complex electric field magnitudes by over 30% during MRI, minimizing tissue heating and system damage, ensuring safe operation during imaging.
Implementation Method 1
shifting the reflection point of electromagnetic waves away from the electrode tip
Implementation Method 2
Exposure to these fields may cause heating to the leads. This heating may result in tissue burns and damage
Data Source
Figure 1a~1b
Figure 2a~2b
Figure 3a~3b
AI summary
A lead (1) for an active implantable medical device (99) comprising: an elongated, biocompatible, electrically non-conductive body (3) having a centre section (4) between a first portion (7) and a body extension (11); a plurality of electrical connectors (6) at the first portion (7); a plurality of electrodes (8) at a second portion (9) of the elongated body (3), wherein the second portion (9) is between the centre section (4) and the body extension (11); and a plurality of electrically conductive filaments (5) inside the elongated body (3) to connect the electrical connectors (6) to corresponding electrodes (8), wherein each of the plurality of electrically conductive filaments (5) include corresponding filament extension sections (13) in the body extension (11).