Neurostimulation Lead CNT Shielding for MRI Compatibility
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Solution Overview
Problem
Existing neurostimulation leads are not MRI-compatible due to absorption of electromagnetic energy, which can cause thermal and voltage stress, potentially leading to tissue or device damage.
Innovation Solution
The neurostimulation lead incorporates one or more electromagnetic shielding layers made of carbon nanotube (CNT) material, which can be further coated with high-permittivity materials like iron or nickel, to protect conductors from electromagnetic interference and improve heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional lead conductors are used in neurostimulation leads, then electrical signal transmission is achieved, but electromagnetic energy absorption occurs causing thermal stress and voltage stress during MRI scans
Solution Approach 1:
An electromagnetic shielding layer is introduced as an intermediary component between the lead conductors and the external electromagnetic fields during MRI scans. This shielding layer acts as a mediator that blocks or redirects electromagnetic energy, preventing it from being absorbed by the conductors and subsequently protecting the IPG from voltage stress while allowing electrical signal transmission to continue uninterrupted
Solution Approach 2:
The shielding layer, which may inherently conduct electricity, is intentionally designed to interact with electromagnetic fields in a controlled manner. By allowing the shielding layer to absorb or redirect electromagnetic energy in a predictable way, the harmful effect of EM field exposure is converted into a manageable interaction that protects the critical IPG components from damage while maintaining lead functionality
2Temperature
If lead conductors are exposed to electromagnetic fields during MRI, then electrical signal transmission continues, but heat is dissipated at the distal end creating thermal stress to tissue
Solution Approach 1:
The electromagnetic shielding layer serves as a thermal intermediary by providing an additional heat dissipation pathway. Instead of heat being concentrated at the distal end of the lead conductors where it causes tissue damage, the shielding layer distributes thermal energy along its structure, acting as a heat sink that protects surrounding tissues from excessive thermal stress
Solution Approach 2:
The shielding layer modifies the thermal parameters of the lead system by introducing a distributed heat dissipation mechanism. This changes the temperature distribution profile from a concentrated point source at the distal end to a more distributed pattern along the lead body, reducing peak temperatures and preventing localized tissue overheating
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 CNT shielding layers effectively reduce the absorption of electromagnetic energy, minimizing thermal and voltage stress on tissues and devices, thereby enhancing MRI compatibility and safety for patients with implanted neurostimulation systems.
Implementation Method 1
The CNT shielding material may take the form of an elongated cord, yarn, fiber or wire structure. Alternatively, the CNT material may be a sheet, coating or film structure.
Implementation Method 2
The one or more forms of CNT shielding may be electrically interconnected in order to distribute heat and electromagnetic energy evenly along the structure of the neurostimulator lead.
Implementation Method 3
In addition, in certain disclosed embodiments, the CNT shielding material of the neurostimulation lead may be further coated with a high-permittivity material such as iron or nickel.
Data Source
AI summary
A system for providing neurostimulation to a patient includes a pulse generator having a housing. An implantable neurostimulation lead is configured to connect with the pulse generator and the pulse generator is configured to generate a plurality of electrical impulses for delivering a neurostimulation treatment to the patient through the lead when the lead is implanted at a target location. The lead includes one or more conductors extending from a proximal end of the lead to one or more neurostimulation electrodes disposed at or near a distal end of the lead. The lead includes an energy absorber including carbon nanotube material and extending substantially along the length of the one or more conductors.