Steerable Sheath with Elastomeric Contrast Reservoir for MRI Safety
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Solution Overview
Problem
Conventional steerable sheaths used in MRI-guided interventional procedures pose safety risks due to RF-induced heating and image artifacts, and there is a need for improved visualization of the sheath tip during MRI scans.
Innovation Solution
A steerable sheath with a reinforced polymer tube and non-metallic pull-wires, incorporating an elastomeric member that becomes visible under MRI when filled with contrast media, allowing for safe navigation and enhanced imaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional steerable sheaths with metallic components are used in MRI-guided procedures, then the sheath provides structural strength and steerability, but RF-induced heating occurs causing safety risks
Solution Approach 1:
The patent removes metallic components from the steerable sheath design, extracting the harmful RF-induced heating effect while maintaining structural integrity through non-metallic materials. The sheath shaft, pull-wires, and reinforcement elements are all constructed from non-metallic materials that are MRI-safe and do not interact with RF fields.
Solution Approach 2:
The patent employs composite material construction throughout the sheath system, using non-metallic materials such as polymers, elastomers, and fiber-reinforced composites. These composite materials provide the necessary mechanical strength, flexibility, and steerability without the RF heating problems associated with metallic components.
2Reliability
If conventional steerable sheaths with metallic components are used, then structural strength is maintained, but image artifacts are produced degrading MRI image quality
Solution Approach 1:
The patent extracts metallic components that generate MRI artifacts, replacing them with non-metallic materials that are MRI-invisible or MRI-safe. This elimination of ferromagnetic and conductive materials prevents distortion of the magnetic field and eliminates artifact generation during MRI scanning.
Solution Approach 2:
The sheath system is constructed from composite non-metallic materials that are specifically selected for their MRI compatibility. These materials do not interfere with the magnetic resonance imaging process, allowing clear visualization of anatomical structures without artifact contamination.
3Measurement precision
If the sheath tip is made visible during MRI, then navigation accuracy is improved, but the sheath structure becomes more complex
Solution Approach 1:
The patent employs contrast media that alter the magnetic resonance signal characteristics, causing the elastomeric member and sheath tip to appear with enhanced visibility on MRI images. This contrast enhancement provides clear visualization of the sheath position and tip location without requiring complex structural modifications.
Solution Approach 2:
The patent introduces contrast media as an intermediary substance that facilitates visualization of the sheath tip during MRI. The contrast media is delivered through the sheath lumen and accumulates in the elastomeric member, creating a visible signal that indicates sheath position without adding mechanical complexity to the sheath structure.
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 reduces RF-induced heating risks, maintains image quality, and improves visualization of the sheath tip during MRI procedures, enabling safer and more effective tool delivery in interventional procedures.
Implementation Method 1
an elastomeric member operably coupled to the proximal end of the steerable shaft and configured to receive contrast media therewithin
Data Source
AI summary
An MR compatible steerable sheath with elastomeric member is provided. The elastomeric member is configured to serve as a reservoir and receive contrast media therewithin. The elastomeric member is positioned on the distal end of the steerable sheath and may circumferentially surround the sheath shaft or be offset from a longitudinal axis thereof. In operation, the contrast media allows a user to view the distal tip of the steerable sheath by virtue of the contrast media contained within the elastomeric member.