Optical Shape Sensing for Live 3D Angiogram Registration
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Solution Overview
Problem
Current methods for simultaneous tool tracking and vessel reconstruction in cardiac interventions face challenges due to limited accuracy from patient movement and the need for multiple x-rays, which increases radiation exposure and reduces real-time capabilities.
Innovation Solution
The method employs optical shape sensing using optical fibers with Fiber Bragg Gratings or Rayleigh scatterers to determine the 3D shape of surgical tools, which is then registered to x-ray images, allowing for real-time 3D angiogram generation with reduced radiation exposure and improved accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If electromagnetic tracking of catheter tip is used to overlay position onto 3D CT scan, then tool tracking capability is provided, but measurement precision deteriorates due to motion from breathing and heart beating
Solution Approach 1:
The patent replaces electromagnetic tracking with optical shape sensing using fiber optic cables that directly measure the physical shape of the catheter. This substitution eliminates the indirect electromagnetic field-based tracking that suffers from motion artifacts, providing direct optical measurement of catheter position and shape that is not affected by breathing or heart beating motions.
Solution Approach 2:
The patent creates an optical copy or representation of the catheter's actual physical shape by measuring light transmission through the transparent catheter. This optical copy accurately represents the true catheter geometry without being influenced by motion, allowing precise overlay on angiographic images despite patient movement.
2Productivity
If rotational cone-beam scan with multiple 2D projections is used to calculate catheter shape, then 3D reconstruction capability is provided, but radiation exposure increases and real-time capability is reduced
Solution Approach 1:
The patent extracts the shape measurement function from the x-ray imaging system itself. Instead of using multiple x-ray projections to infer catheter shape, the system uses a separate optical sensing modality (fiber optic cables) to directly measure catheter shape. This extraction eliminates the need for additional radiation-exposing scans solely for shape reconstruction.
Solution Approach 2:
The patent makes the fiber optic cable serve multiple functions: it provides structural support for the catheter, enables shape measurement through optical sensing, and does not interfere with x-ray imaging. This multi-functionality allows simultaneous shape tracking and angiographic imaging without requiring separate radiation-exposing scans.
3Productivity
If multiple x-ray images are taken at different angles to perform 3D angiogram, then 3D vessel reconstruction is achieved, but radiation dose increases and real-time capability is reduced
Solution Approach 1:
The patent performs preliminary shape measurement continuously using optical sensors before and during the angiographic procedure. This preliminary optical tracking provides real-time catheter shape data that can be immediately overlaid on single-angle angiographic images, eliminating the time required for multiple-angle scanning and 3D reconstruction.
Solution Approach 2:
The patent maintains continuous optical shape sensing throughout the procedure, providing uninterrupted real-time catheter shape information. This continuous measurement allows dynamic updating of the catheter position overlay on angiographic images without interrupting the procedure for additional scans, maintaining continuous useful action for both shape tracking and 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
This approach provides a live, accurate 3D angiogram with reduced radiation exposure and improved real-time capabilities, effectively addressing the limitations of existing methods by using optical shape sensing to register surgical tool curves to x-ray images.
Implementation Method 1
optical fiber cores with scattering sources such as Fiber Bragg Gratings or Rayleigh scatterers disposed in the tool that shift the reflected light wavelength in response to the local strain in the fiber
Implementation Method 2
optical fiber cores with scattering sources such as Fiber Bragg Gratings or Rayleigh scatterers disposed in the tool that shift the reflected light wavelength in response to the local strain in the fiber
Implementation Method 3
An x-ray image is taken of the area where the tool is located, and the 3D tool shape is registered to the 2D segmented image
Data Source
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AI summary
A method, system, and program product are provided for providing a live 3D image of a body lumen. The 3D shape of a flexible surgical tool in the body lumen is determined using optical shape sensing. An x-ray image is taken of the body lumen, with at least one of the body lumen and the surgical tool being radiopaque. The determined 3D surgical tool shape is registered to the x-ray image.