MRI-Compatible Implantable Lead With Coiled Conductor Segments
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Solution Overview
Problem
Conventional implantable electrical stimulation systems are incompatible with magnetic resonance imaging (MRI) due to RF pulses causing unwanted heating and tissue damage, as well as premature failure of electronic components.
Innovation Solution
The design of an implantable lead with a coiled conductor guide and conductor segments that include a first straight segment, a coiled segment, and a second straight segment, which reduces the effects of RF irradiation by distributing the electrical signal in a way that minimizes heating and damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional straight conductors are used in implantable leads, then electrical signal transmission is simple and direct, but RF irradiation during MRI causes unwanted heating and tissue damage
Solution Approach 1:
The conductor is divided into multiple segments including straight segments and coiled segments, rather than using a single continuous straight conductor. This segmentation allows the conductor to distribute RF energy more effectively and reduce localized heating while maintaining electrical connectivity between electrodes and the external world.
Solution Approach 2:
The conductor includes coiled segments with curved geometry instead of purely straight configurations. This curvature distributes the conductor's surface area and electrical current path, reducing the concentration of RF energy and associated heating effects during MRI procedures.
2Reliability
If conventional conductors are used in implantable leads, then the lead structure is simple, but electronic components experience premature failure due to RF-induced currents during MRI
Solution Approach 1:
The conductor path is segmented into multiple sections (straight and coiled segments) that distribute RF-induced currents more evenly throughout the conductor length, preventing concentrated current paths that would otherwise cause premature electronic component failure during MRI procedures.
Solution Approach 2:
The coiled conductor segments act as an intermediary element that modifies the path and distribution of RF-induced currents before they reach electronic components, thereby protecting sensitive electronics from harmful current concentrations during MRI exposure.
3Adaptability or versatility
If straight conductor segments are used, then manufacturing and assembly are straightforward, but the lead lacks RF compatibility during MRI procedures
Solution Approach 1:
The conductor is manufactured as segmented components (straight segments and coiled segments) that can be assembled in a standardized sequence, balancing the need for complex RF-compatible geometry with manufacturing feasibility through modular construction approaches.
Solution Approach 2:
The coiled segments provide the necessary curved geometry for RF compatibility while using standard coiling techniques and materials that remain within acceptable manufacturing complexity, enabling MRI compatibility without prohibitively complex fabrication processes.
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 enhances the compatibility of implantable electrical stimulation systems with MRI, reducing the risk of tissue damage and electronic component failure, thereby ensuring safer and more reliable operation during MRI procedures.
Implementation Method 1
The RF pulses can generate transient signals in the conductors and electrodes of an implanted lead. These signals can have deleterious effects including, for example, unwanted heating of the tissue causing tissue damage
Data Source
AI summary
An implantable lead has an inner core, a plurality of coiled conductor guides, and a plurality of conductors. The inner core defines a plurality of lumens. Each coiled conductor guide defines a plurality of helical lumens. Each coiled conductor guide is disposed in a coiled arrangement over a portion of the inner core. Each of the conductors electrically couples at least one electrode to at least one terminal. At least one of the conductors includes a plurality of units. Each unit includes a first conductor segment extending along the inner core from a beginning point to a first position, a coiled conductor segment disposed at least partially in one of the lumens of the coiled conductor guides and extending from the first position to the second position, and a second conductor segment extending along the inner core from the second position to an endpoint.