Multi-layer coil conductor for MRI-safe implantable leads
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Solution Overview
Problem
Implantable medical leads, such as those used in pacemakers and defibrillators, face challenges when exposed to MRI radiation, as they can induce heat and energy dissipation issues due to their interaction with electromagnetic fields, leading to potential tissue damage and inefficiencies in therapy delivery.
Innovation Solution
The development of multi-layer coil conductors with specific configurations, including close-pitched layers and insulating materials, to minimize heat rise and maximize impedance, thereby reducing energy dissipation and maintaining electrical performance during MRI procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional single-layer conductors are used in implantable leads, then the lead structure is simple and manufacturing is easier, but heat rise and energy dissipation increase when exposed to MRI radiation
Solution Approach 1:
The conductor is divided into multiple independent layers (first coil layer, second coil layer, third coil layer) with different winding configurations. Each layer segments the electromagnetic interaction, allowing individual optimization of heat dissipation characteristics while maintaining overall electrical functionality.
Solution Approach 2:
Different coil layers have different pitch configurations - the first coil layer has a first pitch while the second and third coil layers have a second pitch that is different from the first pitch. This creates local variations in electromagnetic properties throughout the conductor structure, optimizing heat rise characteristics in specific regions while maintaining overall electrical performance.
2Temperature
If multi-layer coil conductors with different pitches are used, then heat rise is minimized and MRI safety is improved, but manufacturing complexity and precision requirements increase
Solution Approach 1:
The conductor is divided into multiple independent layers (first coil layer, second coil layer, third coil layer) with different winding configurations. Each layer segments the electromagnetic interaction, allowing individual optimization of heat dissipation characteristics while maintaining overall electrical functionality.
Solution Approach 2:
Different coil layers have different pitch configurations - the first coil layer has a first pitch while the second and third coil layers have a second pitch that is different from the first pitch. This creates local variations in electromagnetic properties throughout the conductor structure, optimizing heat rise characteristics in specific regions while maintaining overall electrical performance.
3Reliability
If parallel conductive paths are provided with specific resistance values, then electrical performance for therapy delivery is maintained, but energy dissipation during MRI exposure increases
Solution Approach 1:
The conductor is divided into multiple independent layers (first coil layer, second coil layer, third coil layer) with different winding configurations. Each layer segments the electromagnetic interaction, allowing individual optimization of heat dissipation characteristics while maintaining overall electrical functionality.
Solution Approach 2:
The patent specifies that the first and second coil layers have different pitch values, which changes the electromagnetic parameters of the conductor. This parameter variation allows the parallel conductive paths to maintain specific resistance values for reliable therapy delivery while reducing overall energy dissipation during MRI exposure through optimized electromagnetic interaction.
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 multi-layer coil conductor design effectively minimizes temperature rises and energy transfer to body tissue during MRI scans, ensuring safer operation and maintaining therapeutic efficacy for cardiac rhythm management systems.
Implementation Method 1
the multi-layer coil conductor includes a first coil layer including one or more filars wound so as to have a close pitch, and a second coil layer disposed about the first coil layer including one or more filars wound so as to have a close pitch
Implementation Method 2
configured to minimize heat rise when exposed to MRI radiation
Data Source
AI summary
An implantable medical lead exhibits reduced heating under MRI conditions. The lead includes a multi-layer coil conductor including an inner coil layer, a middle coil layer disposed around the inner coil layer, and an outer coil layer disposed around the middle coil layer. Each of the coil layers is characterized by one or more of a filar thickness, a coil pitch, or a coil diameter configured such that the coil conductor exhibits a high inductance when exposed to MRI radiation. Each of the coil layers is electrically connected to the other coil layers to provide parallel conductive paths resulting in a coil conductor resistance suitable for defibrillation lead applications.