MRI Guidewire Carbon Nanotube Coating EMI Shielding

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Solution Overview

Problem

Current MRI-compatible guidewires face issues with induced current and temperature increases, electromagnetic interference, and compatibility with various MRI pulse sequences, leading to safety concerns and suboptimal performance.

Innovation Solution

The development of guidewires with carbon nanotube admixtures in a polymer matrix, exploiting percolation behavior and enhanced electromagnetic compatibility, reduces thermal parasitics and heating, while incorporating fiducial markers and active elements for improved reliability and performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If active catheter types with MRI RF compatible antennae are used, then MRI visualization capability is improved, but induced current and temperature increase up to 70°C occur which are harmful to biological application

Engineering Contradiction:

ImproveMRI visualization capabilityVSAvoidinduced current and temperature increase

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent removes the active RF antenna component from the catheter design, extracting the source of induced current and heating problems while retaining MRI compatibility through passive magnetic properties of the catheter materials

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent converts the harmful induced current effect into a beneficial passive magnetic resonance signal by using ferromagnetic particles embedded in the catheter, which generate detectable signal changes without requiring active RF transmission that causes heating

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Object-affected harmful factors

If passive catheter types are used, then temperature increase is reduced, but artifacts are generated and compatibility with many MRI pulse sequences is lost

Engineering Contradiction:

Improvetemperature controlVSAvoidMRI image quality and pulse sequence compatibility

Core Design Contradiction:

Object-affected harmful factorsVSMeasurement precision

Solution Approach 1:

The patent uses composite materials combining ferromagnetic particles with biocompatible polymer matrices, creating catheters that exhibit both passive temperature stability and active magnetic signal generation capabilities for improved MRI compatibility across multiple pulse sequences

Inventive Principle:

Principle #40Composite materials

3Measurement precision

If semi-active catheter types with capacitors and inductors are used, then fiducial markers are provided, but performance is unsatisfactory due to electromagnetic interference

Engineering Contradiction:

Improvefiducial marker recognitionVSAvoidelectromagnetic interference

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the electronic capacitor-inductor resonant system with a passive magnetic resonance system using ferromagnetic particles, eliminating electromagnetic interference from active electronic components while maintaining fiducial marker functionality through magnetic signal detection

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 provides greater electromagnetic interference shielding, reduced thermal effects, and enhanced reliability, ensuring safer and more effective MRI-guided procedures with improved device speeds and current drives.

Implementation Method 1

The present document also discloses improved guidewire based devices implemented through the use of a novel carbon nanotube (CNT)-admixture into a polymer matrix to circumvent the issues of existing heating or external power requirements

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

the inherent advantages of enhanced electromagnetic interference (EMI) compatibility from nanostructures (such as carbon nanotubes) are exploited

Methodology Applied

Scientific EffectElectromagnetic shielding: Faraday Cage

Data Source

PatentUS11547777B2Thermally robust, electromagnetic interference compatible, devices for non-invasive and invasive surgery

Publication Date: 2023.01.10 RGT UNIV OF CALIFORNIA

AI summary

Techniques to fabricate and use a nanocomposite coating that includes one or more nanotubes such as carbon nanotubes are disclosed. In some examples, a guidewire may include the nanocomposite material. The guidewire is immune to electromagnetic interference, is thermally robust, and is capable of accommodating inactive markers and active electronics.