Catheter Shape Tracking With a Dynamic Spring Model
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Solution Overview
Problem
Existing technologies struggle to accurately model and visualize the changing shape of invasive medical probes, such as catheters, inside moving organs like the heart, due to the complexity of modeling viscous and external forces.
Innovation Solution
A computationally efficient dynamic mass-spring model (DMS) is used to represent the probe as a chain of coupled elastic sections, solving a set of 1st order differential equations based on time-varying boundary conditions, such as measured positions or forces, to calculate the probe's shape in real time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a complex mechanics model accounting for viscous and external forces is used to model the probe shape, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The probe is divided into multiple discrete sections or segments along its length. Each segment is modeled as an independent elastic element (spring-damper system) with defined mechanical properties. This segmentation allows the complex continuous probe structure to be represented by a finite number of simplified discrete elements, making the modeling computationally tractable while maintaining sufficient accuracy for medical applications.
Solution Approach 2:
The model uses time-varying boundary condition parameters (measured positions and forces) to dynamically update the probe shape calculation. By changing the parameters from static to time-varying and incorporating measured data directly into the model, the system achieves accurate real-time shape tracking without requiring complex adaptive modeling algorithms.
2Productivity
If real-time calculation of probe shape is implemented, then productivity is improved, but device complexity increases
Solution Approach 1:
The complex mechanical behavior of the flexible probe is substituted with an equivalent spring-damper mechanical model. This substitution allows the use of well-established, computationally efficient mechanical equations (Hooke's law, damping forces) rather than solving complex partial differential equations, enabling real-time calculations on standard medical system hardware.
Solution Approach 2:
The model explicitly incorporates time-dependent boundary conditions and dynamic force平衡 equations to calculate probe shape at each time step. By using first-order differential equations that can be solved iteratively, the system achieves real-time performance while maintaining dynamic accuracy as the probe moves and deforms during medical procedures.
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
Enables accurate and efficient visualization of the probe's shape within a beating heart, facilitating broader deployment of diagnostic and therapeutic catheter-based systems.
Implementation Method 1
representing sections of the probe as first springs
Implementation Method 2
representing external forces acting on the sections as second springs
Data Source
AI summary
A method includes receiving time-varying boundary condition values measured for a probe inside a cavity of an organ of a patient. A time-dependent shape of the probe is calculated by (a) representing sections of the probe as first springs, (b) representing external forces acting on the sections as second springs, and (c) solving a set of coupled equations of motion, for the first springs and the second springs, so as to meet the time-varying boundary condition values. The shape is presented to a user.