Balloon Catheter Orientation Tracking Under Tissue Deflection
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Solution Overview
Problem
Existing methods for tracking the position and orientation of expandable assemblies in medical catheters, such as balloon catheters, fail to accurately account for deflection caused by pressing against cardiac tissue, leading to inaccurate electrode positioning during procedures like ablation.
Innovation Solution
A secondary catheter with sliding sensors is used to track the deflection of an expandable assembly by modeling the mechanical properties of the catheter and using position signals to estimate orientation, incorporating a cost function minimization algorithm to determine the shape and position of the secondary catheter, which is then used to predict the balloon's orientation and deflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a balloon catheter is pressed against cardiac tissue to perform ablation, then treatment effectiveness is improved, but deflection occurs causing inaccurate electrode positioning
Solution Approach 1:
The system dynamically tracks the catheter's shape and orientation changes in real-time using magnetic sensors and cost function minimization. As the catheter deflects when pressed against tissue, the system continuously updates the position and orientation of electrodes relative to the tissue surface, maintaining positioning accuracy despite shape changes.
Solution Approach 2:
The system employs feedback through magnetic sensors that detect the catheter's position and orientation, feeds this information into a cost function minimization algorithm, and uses the resulting corrected coordinates to accurately represent electrode locations on the tissue surface even when the catheter deflects.
2Measurement precision
If traditional position tracking methods are used for the balloon catheter, then device complexity is reduced, but measurement precision of electrode position deteriorates
Solution Approach 1:
The system introduces magnetic sensors as intermediaries that attach to the catheter and interact with an external magnetic field for position detection. These sensors serve as mediators between the catheter's physical position and the digital tracking system, enabling precise measurement without requiring complex internal instrumentation within the catheter itself.
Solution Approach 2:
The system replaces complex mechanical tracking mechanisms with a magnetic field-based detection approach. Instead of using mechanical encoders or complex linkage systems to track catheter position, the invention uses magnetic sensors and computational cost function minimization to achieve precise position and orientation measurement.
Data Source
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AI summary
A system includes secondary and primary catheters, and a processor. The primary catheter includes shaft for insertion into an organ of a patient, first position sensor disposed on a distal end of the shaft, expandable assembly coupled at the distal end of the shaft, the assembly comprising hollow channel to allow passage of the secondary catheter distally via the assembly, and plurality of second position sensors disposed along a distal end of the secondary catheter, which are configured to indicate a respective plurality of positions along its distal end. The processor is configured to receive the indications of the positions, apply a model of known mechanical properties of the distal end of the secondary catheter to the positions to compute bending profile of the secondary catheter inside the assembly, and based on the computed bending profile, estimate orientation of the assembly relative to the distal end of the shaft.