Capacitive Intravascular Pressure Sensor for Flexible Guide Wire
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Solution Overview
Problem
Current intravascular devices with pressure-sensing components face challenges such as reduced performance due to the need for physical coupling, limited space for electronic components, and stiffness issues, making it difficult to accurately assess stenosis and monitor blood vessel conditions.
Innovation Solution
A guide wire with a radial capacitive pressure-sensing structure and an application-specific integrated circuit (ASIC) is developed, featuring a flexible membrane and conductive member that responds to pressure changes, along with a processing system and interface for data communication, to enhance pressure sensing capabilities within the blood vessels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If guide wires contain electronic components such as pressure sensors, then pressure sensing capability is improved, but handling performance and flexibility deteriorate due to physical coupling requirements, conductor space, and rigid housing
Solution Approach 1:
The patent replaces traditional electronic pressure sensors with a capacitive sensing mechanism that uses electrical fields rather than mechanical components. The capacitive sensor comprises a first capacitive element and a second capacitive element that form a capacitor, where pressure changes modify the capacitance value. This eliminates the need for rigid housings, extensive conductor bundles, and physical coupling mechanisms, thereby maintaining guide wire flexibility and handling performance while achieving accurate pressure sensing.
Solution Approach 2:
The invention changes the measurement parameter from electrical resistance or voltage (traditional sensors) to capacitance. The capacitive sensor measures pressure by detecting changes in capacitance between two electrodes, where the dielectric material between them deforms under pressure. This parameter change enables a more compact design with fewer conductors needed, improving both pressure sensing capability and handling performance.
2Measurement precision
If guide wires contain electronic components, then pressure measurement functionality is improved, but device size and stiffness increase due to housing and conductor requirements
Solution Approach 1:
The patent replaces bulky electronic pressure sensors with a capacitive sensing structure that requires minimal space. The capacitive sensor uses two thin conductive layers separated by a dielectric material, eliminating the need for rigid housings and extensive conductor bundles. This substitution dramatically reduces the volume occupied by the sensing component while maintaining pressure measurement functionality.
Solution Approach 2:
The capacitive sensor elements are integrated within the existing guide wire structure, with the first and second capacitive elements nested within the guide wire's cross-section. The dielectric material is positioned between these elements, creating a compact nested arrangement that fits within the limited space of the guide wire without requiring additional external housing.
3Measurement precision
If traditional capacitive sensors are used, then pressure sensing is achieved, but manufacturing complexity increases due to handling of individual small diaphragm structures
Solution Approach 1:
The patent changes the sensor architecture from a single diaphragm structure to a multi-layer capacitive structure with first and second capacitive elements separated by a dielectric. This parameter change in the structural configuration simplifies manufacturing by eliminating the need for complex diaphragm fabrication and handling, as the capacitive elements can be formed using standard thin-film deposition techniques on flexible substrates.
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 solution improves the accuracy and reliability of pressure sensing within blood vessels, enabling better assessment of stenosis and monitoring of blood vessel conditions, while maintaining the flexibility and maneuverability required for intravascular procedures.
Implementation Method 1
a radial capacitive pressure sensing structure having a flexible membrane positioned around at least a portion of a cavity and a conductive member positioned around at least a portion of the flexible membrane such that the conductive member is displaced by changes in ambient pressure relative to a pressure in the cavity
Data Source
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AI summary
Intravascular devices, systems, and methods are disclosed. In some embodiments, the intravascular devices are guide wires that include a capacitive pressure-sensing component disposed at a distal portion of the guide wire. Methods of making such intravascular devices, including various manufacturing and assembling techniques, are disclosed. Systems associated with such intravascular devices and methods of using such devices and systems are also disclosed.