IVUS Imaging Joint With Thermal Bonding and Flexible Transition
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Solution Overview
Problem
Existing intravascular ultrasound (IVUS) catheters face challenges in achieving both pushability and flexibility for navigating tortuous vasculature while maintaining a seal that does not increase the device diameter and requires minimal assembly labor, with current seals being labor-intensive and prone to fluid intrusion.
Innovation Solution
A flexible elongate member with a polymer outer sheath and inner member, where a polymer filler member thermally reflows to form a seal with the scanner assembly, providing a water-tight joint that enhances pushability, flexibility, and resistance to fluid ingress without significantly increasing the device diameter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the catheter is made stiff to improve pushability, then the catheter can be advanced through vasculature more easily, but the catheter loses flexibility and cannot navigate tortuous pathways
Solution Approach 1:
The catheter is divided into multiple segments with different stiffness characteristics. The proximal portion contains stiffer structural elements for pushability, while the distal portion becomes progressively more flexible to navigate tortuous vasculature. This segmentation allows each portion to optimize its mechanical properties for its specific functional requirement.
Solution Approach 2:
Different portions of the catheter are assigned different mechanical properties tailored to their specific functions. The proximal portion is designed with higher stiffness to transmit pushing forces, while the distal portion transitions to lower stiffness for flexibility and trackability. This local differentiation of material or structural properties resolves the contradiction between overall pushability and local flexibility.
2Reliability
If a traditional seal is used between the catheter and scanner assembly, then fluid intrusion resistance is achieved, but the assembly process becomes labor-intensive and the device diameter increases
Solution Approach 1:
The sealing function is merged with the structural components of the catheter assembly. Instead of using a separate seal component that requires additional assembly steps, the sealing capability is integrated into the catheter body or scanner assembly interface. This integration eliminates the need for separate seal installation while maintaining fluid intrusion resistance.
Solution Approach 2:
Traditional mechanical sealing mechanisms are replaced with an alternative approach that reduces assembly complexity. The patent employs a design where the seal is formed through the inherent geometry and material properties of the catheter components rather than through complex mechanical assembly operations, thereby reducing labor requirements.
3Reliability
If a traditional seal is used between the catheter and scanner assembly, then fluid intrusion resistance is achieved, but the device diameter increases beyond the catheter and scanner assembly diameters
Solution Approach 1:
The sealing structure is nested within the existing catheter and scanner assembly geometry. Instead of adding external sealing components that increase the overall device diameter, the seal is positioned within the internal volume or interface between existing components. This nested arrangement maintains fluid intrusion resistance while preserving the original device diameter profile.
4Reliability
If the distal end of the outer sheath is made larger to fit over the scanner assembly, then the seal integrity is improved, but the device diameter increases
Solution Approach 1:
Instead of increasing the radial dimension (diameter) of the outer sheath distal end, the sealing mechanism utilizes the longitudinal dimension or internal geometry. The seal integrity is achieved through axial positioning, internal reinforcement structures, or material properties rather than through increased outer diameter, thereby maintaining a compact device profile.
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 enables IVUS catheters to navigate complex vasculature with improved pushability and flexibility, while maintaining a compact profile and reducing assembly complexity, with a seal that is both durable and resistant to fluid intrusion.
Implementation Method 1
When heated, the filler member thermally reflows and thermally bonds with the polymer inner member and polymer outer member, forming a seal that holds the outer member tight (e.g., water-tight) against the scanner assembly.
Implementation Method 2
When heated, the filler member thermally reflows and thermally bonds with the polymer inner member and polymer outer member, forming a seal
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
An intraluminal imaging device includes a flexible elongate member configured to be positioned within a body lumen of a patient. The flexible elongate member includes a first polymer. An ultrasound scanner assembly is positioned at a distal end of the flexible elongate member, and is configured to obtain ultrasound imaging data while positioned within the body lumen. A filler member including a second polymer is positioned at the distal end of the flexible elongate member, and is coupled to the flexible elongate member via thermal reflow of the first polymer and the second polymer to seal a joint between the flexible elongate member and the ultrasound scanner assembly.