Intravascular Imaging Catheter Force Detection and Retraction
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Solution Overview
Problem
Catheters with imaging components face issues of kinking and damage due to the rigidity of the imaging tip, which can lead to penetration of the outer sheath and potential injury, especially when advanced into kinked or tightly curved vessels.
Innovation Solution
A pullback and rotation unit with force error detection and remediation is implemented, featuring a rotor with sensors to monitor axial forces and automatically retract when thresholds are exceeded, alleviating kinking and preventing damage by relieving axial forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the imaging tip is made rigid to accommodate imaging sensors, then the imaging components can be properly mounted and function, but the catheter may kink or damage the outer sheath when advanced into curved vessels
Solution Approach 1:
The force sensor detects excessive axial forces on the torque cable before they cause kinking or damage to the outer sheath. The controller then automatically retracts the torque cable proximally to relieve the force, preventing the harmful effect from occurring in the first place
Solution Approach 2:
A force sensor continuously monitors the axial force on the torque cable and provides real-time feedback to the controller. When the force exceeds a predetermined threshold, the controller automatically actuates the torque cable to retract, creating a closed-loop feedback system that prevents kinking and damage
2Length of moving object
If the imaging tip is advanced distally into the outer sheath, then the catheter can be positioned in the vessel, but excessive axial force may cause the imaging tip to penetrate the outer sheath creating injury risk
Solution Approach 1:
The force sensor and controller system detects excessive axial force before the imaging tip can penetrate the outer sheath. The automatic retraction mechanism relieves the force proactively, preventing penetration and the associated injury risk before they can occur
Solution Approach 2:
The continuous monitoring of axial force by the sensor and the automatic corrective action by the controller create a feedback loop that prevents the imaging tip from exerting enough force to penetrate the outer sheath, thereby eliminating the injury risk
3Manufacturing precision
If a torque cable is used to position the imaging tip, then the imaging components can be precisely positioned and oriented, but the system lacks force monitoring and automatic protection against error conditions
Solution Approach 1:
The force sensor provides continuous feedback on the axial force experienced by the torque cable. When excessive force is detected, the controller automatically retracts the cable to relieve the force, creating a protective feedback loop that enhances system reliability without compromising positioning precision
Solution Approach 2:
The system performs self-diagnosis through the force sensor and self-correction through automatic retraction when excessive force is detected. This self-service capability allows the system to protect itself against force error conditions without requiring external intervention, thereby improving reliability
Data Source
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AI summary
An intravascular imaging system includes a catheter with an elongate outer sheath and a torque cable axially translatable and rotatable in the elongate outer sheath, a pullback and rotation unit for axially translating and rotating the torque cable, a sensor configured to provide an output indicative of an axial force exerted by the torque cable on a rotor in the pullback and rotation unit, and a controller configured to cause the pullback and rotation unit to operate in a remedial mode if the output exceeds a predetermined threshold.