Catheter Positioning Correction via Vascular Map Optimization
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Solution Overview
Problem
Existing methods for determining the position of a catheter in a vascular system, particularly in highly branched and circumflex vessels, are not sufficiently accurate due to interference from external magnetic fields and magnetically active materials, leading to inaccuracies in position and orientation measurement.
Innovation Solution
A device and method using multiple localizers with a data processing unit to correct measured positions and orientations by minimizing deviations from a vascular map, considering a quality dimension that accounts for both positional and orientational deviations, and employing electromagnetic localizing devices to mitigate interference effects, while also providing continuous transformation and warning mechanisms for potential vessel penetration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If magnetic localizing devices are used to measure catheter position, then position measurement can be achieved, but measurement precision deteriorates due to interference from external magnetic fields and magnetically active materials
Solution Approach 1:
The patent introduces an intermediary transformation process that maps measured positions (affected by interference) to corrected positions on the vascular map. The transformation function acts as a mediator that compensates for measurement errors caused by magnetic interference, converting inaccurate raw measurements into accurate positional information on the vascular map.
Solution Approach 2:
The system employs feedback by continuously comparing measured positions with the vascular map and adjusting the transformation function accordingly. The measured positions serve as feedback to update the transformation, which in turn improves the accuracy of subsequent position determinations, creating a self-correcting system that compensates for magnetic interference.
2Measurement precision
If multiple localizers are used to improve position accuracy, then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent makes the localizers multi-functional by enabling them to serve both position determination and orientation determination purposes. The same localizer measurements are used for both functions, eliminating the need for separate sensing systems and reducing overall device complexity while maintaining high measurement precision.
Solution Approach 2:
The system merges position and orientation information into a unified transformation function that maps both types of data to the vascular map simultaneously. This consolidation allows multiple localizers to work together efficiently, sharing processing resources and reducing system complexity while improving measurement accuracy.
3Measurement precision
If continuous X-ray fluoroscopic observation with contrast agents is used to obtain precise catheter position knowledge, then measurement precision improves, but harmful factors increase due to patient exposure
Solution Approach 1:
The patent creates a virtual copy of the catheter position and orientation on the vascular map through mathematical transformation rather than direct visual observation. This virtual representation provides sufficient positional knowledge for navigation without requiring continuous X-ray imaging, thereby eliminating radiation exposure and contrast agent injection while maintaining adequate measurement precision.
Solution Approach 2:
The system replaces the mechanical/optical X-ray imaging system with an electromagnetic field-based localizing system combined with computational transformation. This substitution eliminates the need for ionizing radiation and contrast agents while providing continuous, real-time catheter position and orientation information through non-invasive magnetic field measurements.
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
The solution achieves high accuracy in determining catheter position and orientation, especially in complex vascular layouts, by minimizing positional errors and compensating for motion artifacts, and provides warnings for potential vessel injuries, thus enhancing the precision and safety of catheter navigation.
Implementation Method 1
at least one of the localizers is a magnetic field sensor forming part of an electromagnetic localizing device. In electromagnetic localizing devices, field generators generate a magnetic field inhomogeneous in space and/or time, wherein the value and direction of the field strength can be measured by magnetic field sensors
Data Source
AI summary
The invention relates to a device and a method for the determination of the position of a catheter in a vascular system (8). In this, the measured positions (r1, r2) of two magnetic localizers at the tip of a catheter are displaced by correction vectors (k1, k2) while optimizing a quality dimension. The quality dimension includes a component taking account both of the deviation of the measured positions (r1, r2) from the vascular layout and of the deviation of the associated orientation (r2−r1) from the orientation of the vascular layout according to a vascular map. In addition, the quality dimension may include components which evaluate the measured shape of the catheter compared to the vascular map. An additional correction step can further ensure that the corrected positions (r1′, r2″) correspond to the preset fixed distance (d) of the localizers (4, 5).