Virtual Endoscopic Visualization for Narrow Passage Navigation
Solution Overview
Problem
In image-guided surgery, particularly in procedures involving narrow body passages like the nasal sinuses, existing methods struggle to provide effective visualization of medical tools due to the limitations of rigid endoscopes and the difficulty in registering different imaging modalities, such as CT images and electromagnetic tracking systems.
Innovation Solution
A method and system that register a position sensing system with a 3D CT image within a common frame of reference, allowing for the specification and rendering of virtual endoscopic images from multiple viewpoints, enabling the tracking and visualization of medical tools within narrow passages by using electromagnetic tracking and virtual cameras positioned along the tool's route, which can change perspective to maintain the tool in view.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rigid endoscopes are used to visualize narrow passages, then direct visualization is achieved, but the complexity of the procedure increases and precision is reduced due to difficulty in navigation
Solution Approach 1:
The patent creates virtual copies of the narrow passage anatomy from pre-acquired CT images and uses virtual cameras to simulate endoscopic views. This virtual representation allows practitioners to navigate and visualize the passage without physically inserting rigid endoscopes, thereby reducing procedural complexity while maintaining visualization accuracy.
Solution Approach 2:
The patent replaces the mechanical rigid endoscope system with an electromagnetic tracking system combined with virtual reality visualization. The electromagnetic fields track the medical tool's position and orientation, and virtual cameras render endoscopic-like views from those coordinates, eliminating the need for mechanical endoscope insertion and improving both ease of operation and precision.
2Measurement precision
If CT images and electromagnetic tracking systems are registered, then accurate tool positioning is achieved, but the difficulty of registering different imaging modalities increases
Solution Approach 1:
The patent introduces a frame with electromagnetic field generators as an intermediary between the CT imaging system and the tracking system. The frame is registered to the patient's anatomy using CT images, and electromagnetic tracking is calibrated to this frame, creating a common reference system that simplifies the registration process while maintaining high positioning accuracy.
3Loss of information
If virtual cameras are positioned along the tool's route, then comprehensive visualization is achieved, but the system complexity increases
Solution Approach 1:
The patent pre-positions multiple virtual cameras at strategic locations along the anticipated tool route through the narrow passage before the procedure begins. These virtual cameras are configured to capture views from key anatomical locations, ensuring comprehensive visualization coverage is ready in advance, reducing the need for complex real-time camera positioning during the procedure.
Solution Approach 2:
The patent implements dynamic virtual camera positioning that automatically adjusts camera locations and orientations based on the real-time tracked position of the medical tool. As the tool moves through the passage, the virtual cameras follow and reposition themselves to maintain optimal viewing angles, providing comprehensive visualization without requiring manual intervention or complex fixed camera arrays.
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 enhanced visualization and control of medical tools during procedures like sinuplasty by generating virtual endoscopic views that mimic actual endoscope perspectives, allowing for more intuitive guidance and improved precision in navigating tools through tight spaces without the need for rigid endoscopes.
Implementation Method 1
an electromagnetic tracking system, which includes one or more magnetic field generators positioned around the part of the body and a magnetic field sensor at a distal end of the medical tool
Data Source
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Figure 3~4
AI summary
A method for visualization includes registering, within a common frame of reference, a position sensing system and a three-dimensional (3D) computerized tomography (CT) image of at least a part of a body of a patient. A location and orientation of at least one virtual camera are specified within the common frame of reference. Coordinates of a medical tool moving within a passage in the body are tracked using the position sensing system. A virtual endoscopic image, based on the 3D CT image, of the passage in the body is rendered and displayed from the specified location and orientation, including an animated representation of the medical tool positioned in the virtual endoscopic image in accordance with the tracked coordinates.