Catheter Sensor Core with Ferromagnetic Windings for Signal Strength
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Solution Overview
Problem
Current methods for manufacturing elongated catheters with sensors face challenges in signal improvement and manufacturing ease, particularly due to constraints on wire diameter, strength, and the number of turns required, which limit design flexibility and increase production complexity.
Innovation Solution
The catheter design incorporates a core with ferromagnetic properties around which a thinner wire is wrapped, forming a twisted pair, and includes a metallic reinforcement structure and polymeric liners to enhance signal gain and reduce noise, while allowing for articulation of the distal portion through a pull wire mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thicker wire is used for the sensor, then the signal strength is improved, but the wire diameter constraint is violated and the sensor size increases
Solution Approach 1:
The patent applies nesting by wrapping the wire around a ferromagnetic core in multiple concentric layers, creating a nested structure where the magnetic field is concentrated within the core and wire windings. This allows achieving strong signal output through multiple turns of thin wire rather than using a single thick wire, thus violating the wire diameter constraint while maintaining signal strength.
Solution Approach 2:
The patent combines ferromagnetic core material with conductive wire material to create a composite sensor structure. The ferromagnetic core amplifies the magnetic field, allowing the use of thinner wire while maintaining or improving signal strength. This composite approach resolves the contradiction between wire thickness and signal strength.
2Measurement precision
If the number of wire turns is increased to improve signal resolution, then measurement precision is improved, but the sensor complexity and manufacturing difficulty increase
Solution Approach 1:
The patent applies preliminary action by pre-forming the ferromagnetic core with integrated wire windings before inserting the assembly into the catheter. The core is manufactured with channels or grooves that guide wire placement, and the wire is wrapped around the core in a controlled manner during the core formation process itself, rather than attempting to assemble pre-made components. This reduces manufacturing complexity while achieving high signal resolution through multiple turns.
3Volume of moving object
If the sensor is miniaturized to fit within the catheter, then the device size is reduced, but the signal strength and measurement capability deteriorate
Solution Approach 1:
The patent applies parameter changes by utilizing the ferromagnetic core's high magnetic permeability to concentrate and amplify the magnetic field within a compact volume. The core's magnetic properties allow the sensor to achieve strong signal output despite miniaturization. Additionally, the wire winding density and turn count are optimized to maximize signal strength within the constrained space, resolving the contradiction between size and signal strength.
4Strength
If the catheter structure is made more rigid to support the sensor, then structural strength is improved, but the catheter flexibility and ease of navigation deteriorate
Solution Approach 1:
The patent applies nesting by integrating the sensor assembly (wire wrapped around core) within the existing catheter structure, placing it inside the inner liner or between the inner and outer liners. This nested placement provides mechanical support for the sensor without requiring additional external reinforcement structures, thus maintaining catheter flexibility while supporting the sensor's structural integrity.
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
This design enhances signal resolution, reduces noise, and increases the resistance to crush, allowing for more flexible and effective navigation and imaging under fluoroscopy, while maintaining a compact size and ease of manufacturing.
Implementation Method 1
The catheter design incorporates a core with ferromagnetic properties around which a thinner wire is wrapped
Implementation Method 2
a first portion of the wire is formed in a plurality of windings wrapped around the reduced diameter portion of the core
Data Source
AI summary
A catheter including a catheter body (60) formed of a polymeric material and having a lumen therethrough, a metallic reinforcement structure in contact with the polymeric material, a core, and a sensor wire with a first portion (71) formed in a plurality of windings wrapped around the core and a second portion formed as a twisted pair (80) extending the catheter body (60). The catheter may include a pull wire anchored to the core.