MRI-Safe Implantable Lead With Conductive Jacket
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Solution Overview
Problem
Implantable neurostimulation systems face issues with RF-induced heating during MRI scans, as they can generate significant heat due to induced RF currents, posing risks to patients and device integrity.
Innovation Solution
A medical lead with a conductive jacket is designed to dissipate or direct induced RF energy to the patient's body, reducing heat generation at the stimulation electrodes by providing a path for RF energy along the lead's length, utilizing materials with high dielectric constants and structural features like pores or multi-layered jackets to enhance capacitance and conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional implantable lead is used during MRI scanning, then the lead can deliver electrical stimulation to neural tissue, but the lead generates significant heat due to induced RF currents, posing risks to patient safety and device integrity
Solution Approach 1:
The patent applies the principle of converting harm into benefit by transforming the harmful induced RF currents into a beneficial cooling effect. The conductive jacket is designed to intentionally generate heat through controlled RF current paths that bypass the stimulation electrodes, thereby protecting the electrodes from excessive heating while safely dissipating energy through the jacket structure that is better suited for heat management.
Solution Approach 2:
The conductive jacket serves as an intermediary element between the RF field and the stimulation electrodes. It provides a dedicated pathway for RF current flow that isolates the electrodes from direct RF exposure, thereby mediating the interaction between the MRI environment and the sensitive electrode-tissue interface to prevent harmful thermal effects.
2Reliability
If the lead structure is modified to reduce RF-induced heating, then patient safety during MRI is improved, but the lead's ability to deliver effective electrical stimulation may be compromised
Solution Approach 1:
The lead structure is segmented into functionally distinct components: the conductive jacket handles RF current management and thermal dissipation, while the stimulation electrodes maintain their optimized design for electrical nerve stimulation. This segmentation allows each component to be independently optimized for its specific function without compromising the other, enabling safe MRI operation while preserving effective stimulation delivery.
Solution Approach 2:
Different portions of the lead structure are assigned different electrical and thermal properties. The conductive jacket is designed with specific conductivity and thermal characteristics for RF energy management, while the electrodes maintain their specialized properties for efficient neural stimulation. This local differentiation of material and structural properties enables simultaneous optimization for both MRI safety and stimulation effectiveness.
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 effectively reduces unwanted heat at the lead's electrodes during MRI procedures, ensuring safer operation of implantable neurostimulation systems in MRI environments and minimizing potential damage to the devices.
Implementation Method 1
A medical lead with a conductive jacket is designed to dissipate or direct induced RF energy to the patient's body, reducing heat generation at the stimulation electrodes by providing a path for RF energy along the lead's length
Implementation Method 2
The conductive jacket is designed to dissipate or direct induced RF energy to the patient's body, reducing heat generation at the stimulation electrodes
Implementation Method 3
utilizing materials with high dielectric constants and structural features like pores or multi-layered jackets to enhance capacitance and conductivity
Data Source
AI summary
A stimulation lead is configured to be implanted into a patient's body and includes at least one distal stimulation electrode and at least one conductive filer electrically coupled to the distal stimulation electrode. A jacket is provided for housing the conductive filer and providing a path distributed along at least a portion of the length of the lead for conducting induced RF energy from the filer to the patient's body.