IVUS Catheter Shaft Segmentation for Ultrasonic Clarity
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Solution Overview
Problem
Conventional IVUS catheters face challenges in acquiring clear images due to the hindrance of ultrasonic wave transmission and reception at the joint parts between the first and second shafts, caused by adhesives or welding distortions, which limits the effectiveness of the IVUS device.
Innovation Solution
The IVUS catheter design features a first shaft with a guide wire lumen and a second shaft with an imaging lumen, where the second shaft is not joined to the first shaft in a specific distal region, allowing for uninterrupted ultrasonic wave transmission and reception, and is joined only in proximal regions to maintain flexibility and operability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the second shaft is joined to the first shaft along its entire length, then the structural strength and rigidity of the catheter are improved, but the transmission and reception of ultrasonic waves by the transducer are hindered at the joint part
Solution Approach 1:
The second shaft is divided into a joined portion (proximal to the transducer) and an unjoined portion (distal to the transducer). The unjoined portion allows ultrasonic waves to pass freely without interference from adhesives or welding, while the joined portion provides structural strength. This segmentation resolves the contradiction by spatially separating the functional requirements of strength and ultrasonic transmission.
Solution Approach 2:
Different joining states are applied to different portions of the second shaft based on local requirements. The proximal portion (where structural support is needed) is joined to the first shaft, while the distal portion (where ultrasonic transmission is critical) remains unjoined. This local differentiation allows each region to optimize its performance for its specific function.
2Strength
If the first shaft and the second shaft are joined to each other by welding, then the joint strength is improved, but distortion occurs in the shafts and the range in which ultrasonic wave transmission is hindered increases
Solution Approach 1:
The second shaft is segmented into a joined portion and an unjoined portion. The joined portion undergoes welding to achieve strong structural connection, while the unjoined portion remains free from welding-induced distortion. This segmentation isolates the thermal effects of welding to a limited region, preventing distortion from propagating to the transducer area.
Solution Approach 2:
The unjoined portion is extracted from the welded assembly, removing it from the zone affected by welding heat and distortion. This extracted portion maintains its original shape and dimensional stability, ensuring that ultrasonic wave transmission is not hindered by shaft distortion.
3Reliability
If a large opening is provided at a position facing the transducer in the first shaft, then ultrasonic wave transmission is improved, but the structural integrity and flexibility of the catheter are compromised
Solution Approach 1:
Instead of creating a large opening in the first shaft, the design segments the second shaft into joined and unjoined portions. The unjoined portion of the second shaft provides the necessary acoustic pathway for ultrasonic waves, while the first shaft maintains its complete cylindrical structure and structural integrity. This approach achieves ultrasonic transmission without compromising catheter strength.
Solution Approach 2:
The unjoined portion of the second shaft acts as an intermediary acoustic pathway, allowing ultrasonic waves to transmit from the transducer to the patient's vasculature without requiring modifications to the first shaft. This intermediary structure preserves the structural integrity of the primary support shaft while enabling effective ultrasonic transmission.
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 image clarity by minimizing interference from adhesives and welding distortions, improving the flexibility and kink resistance of the catheter, enabling more accurate positioning and penetration during procedures.
Implementation Method 1
transmission and reception of ultrasonic waves by the transducer of the IVUS device inserted into the IVUS lumen of the second shaft
Data Source
AI summary
A catheter includes a shaft part having a first shaft and a second shaft. The first shaft is a cylindrical member having a guide wire lumen into which a guide wire is inserted. The second shaft is a cylindrical member having an imaging lumen into which an imaging device for acquiring an image of an interior of a living body lumen is inserted, and is disposed alongside the first shaft. In a first region from a first position at a distal end portion of the shaft part to a second position further on a proximal end side than the first position, the second shaft is not joined to the first shaft. In a second region that is continuous with the first region and that is further on the proximal end side than the first region, the second shaft is joined to the first shaft.