MRI Compatible Steerable Sheath and Control Handle
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Solution Overview
Problem
Conventional steerable sheaths and control handles are not compatible with MRI environments, leading to RF-induced heating, image artifacts, and unwanted device movement due to metallic materials, which pose safety risks and degrade image quality during interventional procedures.
Innovation Solution
A steerable sheath and control handle constructed from non-magnetic materials, such as reinforced polymer tubes with non-metallic reinforcing materials and pull-wires, and using paramagnetic or diamagnetic materials in the control handle, along with active or passive visualization markers, to enable safe and effective tool delivery and tracking within MRI environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metallic materials are used in steerable sheaths and control handles, then structural strength and steerability are improved, but RF-induced heating and image artifacts occur in MRI environments
Solution Approach 1:
The patent changes the material parameter from metallic to non-magnetic alloys or polymers with specific magnetic susceptibility values. The control handle uses paramagnetic or diamagnetic materials that minimize RF induced heating while maintaining structural integrity and steerability in MRI environments.
Solution Approach 2:
The patent employs composite material structures combining non-magnetic alloys, polymers, and reinforcing materials that provide necessary mechanical strength without the harmful RF heating properties of traditional metallic materials.
2Strength
If metallic materials are used in steerable sheaths and control handles, then structural strength and steerability are improved, but image artifacts and unwanted device movement occur in MRI environments
Solution Approach 1:
The patent changes the magnetic susceptibility parameter of the materials used in the sheath and control handle to be compatible with MRI environments, eliminating image artifacts and unwanted device movement while preserving structural strength.
Solution Approach 2:
The patent converts the potential harm of metallic materials causing image artifacts into a benefit by using non-magnetic materials that are actually advantageous for maintaining image quality and device stability in MRI environments.
3Object-affected harmful factors
If non-magnetic materials are used in steerable sheaths and control handles, then RF-induced heating and image artifacts are eliminated, but manufacturing complexity increases
Solution Approach 1:
The patent specifies particular material parameters (magnetic susceptibility, strength, flexibility) that balance RF safety with manufacturability, selecting materials that are both MRI compatible and practical to manufacture.
4Reliability
If non-magnetic materials are used in steerable sheaths and control handles, then image quality is maintained, but device complexity increases
Solution Approach 1:
The patent adjusts material parameters to achieve the desired balance between image quality maintenance and device simplicity, selecting non-magnetic materials that provide necessary functionality without excessive complexity.
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 allows for safe and effective delivery of tools into the body during MRI procedures without RF-induced heating or image artifacts, maintaining clinical-grade image quality and preventing unwanted device movement, thus enhancing the safety and efficacy of interventional procedures.
Implementation Method 1
MRI uses three fields to image patient anatomy: a large static magnetic field, a time-varying magnetic gradient field, and a radiofrequency (RF) electromagnetic field.
Implementation Method 2
One important safety risk is the heating that may result from an interaction between the RF field of the MRI scanner and the medical device (RF-induced heating), especially medical devices that have elongated conductive structures
Implementation Method 3
The static field of the MRI will cause magnetically induced displacement torque on any device containing ferromagnetic materials and has the potential to cause unwanted device movement.
Data Source
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AI summary
An MR compatible deflectable catheter and method of using the same is provided. The MR compatible deflectable catheter includes a steerable sheath having a tubular shaft. The tubular shaft receives first and second longitudinal movement wires at a distal end thereof. A control handle is coupled to a proximal end of the first and second longitudinal movement wires and causes longitudinal movement of the wires.