Catheter Tip Superimposition on Moving Imager Images
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Solution Overview
Problem
Existing medical navigation systems face challenges in accurately superimposing the representation of a catheter tip on real-time medical images due to differences between 3D optical and magnetic coordinate systems, leading to processing complexities and potential distortions.
Innovation Solution
A method and system that determine intrinsic and extrinsic parameters to convert magnetic positioning system coordinates into 2D optical coordinates, allowing for accurate superimposition of the catheter tip on images by interpolating or extrapolating between physical zoom settings, and using a distortion correction model to modify the tip's projection on distorted images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If magnetic positioning system coordinates are directly superimposed on optical images, then the catheter tip position can be displayed, but coordinate system mismatches cause alignment inaccuracies and distortions
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing transformation parameters (intrinsic and extrinsic parameters) that map magnetic coordinate system to optical coordinate system before the actual medical procedure. This allows real-time accurate superimposition without complex runtime calculations, resolving the contradiction between position accuracy and computational complexity.
Solution Approach 2:
The patent changes parameters by introducing intrinsic parameters (focal length, principal point) and extrinsic parameters (rotation and translation) that characterize the relationship between magnetic and optical coordinate systems. By adjusting and storing these parameters, the system achieves accurate coordinate transformation while simplifying real-time processing.
2Measurement precision
If real-time image processing is performed to correct distortions, then accurate catheter tip superimposition is achieved, but processing time and computational load increase
Solution Approach 1:
The patent performs distortion correction parameters calculation in advance during system setup or calibration phase, storing the correction model for rapid application during procedures. This preliminary computation eliminates the need for time-consuming real-time distortion correction, maintaining accuracy while minimizing processing time.
Solution Approach 2:
The patent creates a corrected copy of the optical image coordinate system that accounts for distortions, allowing the magnetic catheter tip position to be accurately superimposed on the pre-corrected image without performing complex real-time distortion calculations on the original image data.
3Measurement precision
If extensive real-time image processing is performed to align coordinate systems, then accurate catheter tip display is achieved, but system productivity and operational efficiency decrease
Solution Approach 1:
The patent establishes the coordinate transformation model and stores all necessary parameters before the medical procedure begins. This preliminary setup enables rapid, efficient operations during the actual procedure without repeated complex calculations, thereby maintaining high precision while improving operational efficiency and productivity.
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 enables accurate and efficient display of the catheter tip's position on real-time images without requiring extensive real-time image processing, reducing processing load and ensuring precise alignment of coordinate systems.
Implementation Method 1
a magnetic field generator (118) firmly coupled with a moving portion of the moving imager (102)... producing a magnetic field (142)
Data Source
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AI summary
Method for displaying a representation of the tip of a medical device located within a body region of interest of the body of a patient, on an image of the body region of interest, the image being acquired by an image detector of a moving imager, the method including the procedures of acquiring a medical positioning system (MPS) sensor image of an MPS sensor, determining a set of intrinsic and extrinsic parameters, determining two-dimensional optical coordinates of the tip of the medical device, superimposing the representation of the tip of the medical device, on the image of the body region of interest, and displaying the representation of the tip of the medical device superimposed on the image of the body region of interest, the MPS sensor image of the MPS sensor being acquired by the image detector, at a physical zoom setting of the image detector respective of the image, and at a selected image detector region of interest setting of the image detector, the MPS sensor being associated with an MPS, the MPS sensor responding to an electromagnetic field generated by an electromagnetic field generator, firmly coupled with a moving portion of the moving imager, the set of intrinsic and extrinsic parameters being determined according to sensor image coordinates of the MPS sensor image, in a two-dimensional optical coordinate system respective of the image detector, and according to non-real-time MPS coordinates of the MPS sensor, in an MPS coordinate system respective of the MPS, the two-dimensional optical coordinates of the tip of the medical device being determined according to the physical zoom setting, according to the set of intrinsic and extrinsic parameters, according to the selected image detector region of interest setting, and according to real-time MPS coordinates of an MPS sensor located at the tip of the medical device, the representation of the tip of the medical device, being superimposed on the image of the body region of interest, according to the two-dimensional optical coordinates.