Catheter Navigation Using IVUS Roadmap Correlation
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Solution Overview
Problem
Current navigation methods for catheters in intravascular procedures rely heavily on X-ray fluoroscopy, which exposes patients to radiation and limits visibility of vessel walls and surrounding tissue, and are costly and complex when combined with intravascular ultrasound.
Innovation Solution
An apparatus and method using a sensor probe, such as intravascular ultrasound (IVUS) or optical coherence tomography (OCT), to create a roadmap of the vessel by acquiring and storing local images, allowing for accurate navigation without radiation exposure by correlating current images with a stored sequence, enabling precise positioning of instruments like stents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If X-ray fluoroscopy is used to guide catheter navigation, then real-time imaging of the vessel path is achieved, but patient radiation exposure increases and vessel walls/tissue visibility deteriorates
Solution Approach 1:
The patent replaces the X-ray imaging system with an intravascular ultrasound (IVUS) system that uses acoustic waves instead of electromagnetic radiation. The IVUS probe emits ultrasound waves into the vessel wall and surrounding tissue, receives the reflected echoes, and reconstructs cross-sectional images, thereby eliminating patient radiation exposure while maintaining navigation capability
Solution Approach 2:
The patent introduces a roadmap as an intermediary representation that correlates IVUS cross-sectional images with the catheter's longitudinal position in the vessel. This roadmap serves as a reference guide that allows operators to navigate accurately without relying on continuous X-ray fluoroscopy, thus reducing radiation exposure while maintaining navigation reliability
2Loss of information
If contrast medium is injected to improve vessel visibility in X-ray images, then vessel path visualization improves, but patient stress increases and imaging of vessel walls/tissue deteriorates
Solution Approach 1:
The patent substitutes contrast medium injection with intravascular ultrasound imaging that directly visualizes vessel walls, plaque deposits, and surrounding tissue through acoustic wave reflection. This eliminates the need for contrast medium while providing superior soft tissue imaging capability and avoiding patient stress from contrast injection
Solution Approach 2:
The patent changes the imaging modality parameter from X-ray absorption (which requires contrast medium) to ultrasound reflection (which provides intrinsic soft tissue contrast). This parameter change allows visualization of vessel walls and tissue structures without introducing contrast medium, thereby eliminating the associated patient stress
3Loss of information
If IVUS images are combined with X-ray images to improve three-dimensional representation, then vessel shape visualization improves, but device complexity increases and radiation exposure increases
Solution Approach 1:
The patent extracts and eliminates the X-ray imaging component from the combined imaging system, relying solely on IVUS cross-sectional images. By processing and displaying a sequence of IVUS cross-sections in relation to the catheter's longitudinal position, the system achieves three-dimensional vessel representation without the complexity and radiation exposure of dual-modality imaging
Solution Approach 2:
The patent transforms two-dimensional IVUS cross-sectional images into a three-dimensional representation by correlating them with the catheter's longitudinal position along the vessel axis. This creates a virtual longitudinal section or roadmap that displays vessel morphology, cross-sectional area changes, and plaque characteristics in a three-dimensional context using only ultrasound data
4Measurement precision
If X-ray images are used to determine catheter position, then navigation accuracy improves, but patient radiation exposure increases
Solution Approach 1:
The patent replaces X-ray-based catheter position determination with IVUS-based positioning. The IVUS probe continuously acquires cross-sectional images, and the system correlates these images with a pre-established roadmap to precisely determine the catheter's longitudinal position in the vessel without any radiation exposure
Solution Approach 2:
The patent implements a feedback mechanism where IVUS cross-sectional images are continuously compared with the stored roadmap to update and refine the catheter position determination. This real-time feedback allows accurate navigation by constantly monitoring the match between actual IVUS images and expected roadmap features, eliminating the need for continuous X-ray imaging
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
Enables accurate, low-stress navigation and positioning of catheters within vessels with minimal radiation exposure, using IVUS or OCT to generate and correlate cross-sectional images, reducing patient stress and procedural complexity.
Implementation Method 1
an intravascular ultrasound system (IVUS)... Cross-sectional images of the vessel (images perpendicular to the axis of the vessel) can be obtained with an IVUS
Implementation Method 2
optical coherence tomography (OCT)... to create a roadmap of the vessel by acquiring and storing local images
Data Source
AI summary
The invention relates to the assistance of the navigation of a catheter (1) in a vessel (2). A sequence of cross-sectional images of the portion of the vessel that is of interest is first obtained with the help of an intravascular ultrasound (IVUS) probe (3) and stored as a roadmap of the vessel. A cross-sectional image (10) that is obtained at the current position of the IVUS probe (3) can then be sorted to the position on the roadmap that is the best fit. A model (3′) of the probe, and a model (11′) of the instrument (a stent (11), for example) coupled to the probe, can be shown on a display (6) at the corresponding position on the roadmap.