Catheter Position Verification Using Hybrid Magnetic-Impedance Tracking
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Solution Overview
Problem
Magnetic localization systems in medical devices are susceptible to errors due to magnetic field distortions caused by ferrous or metallic objects, leading to inaccurate positioning of catheters within the body.
Innovation Solution
A hybrid magnetic and impedance tracking system that differentiates between magnetic field distortions and physical movement by using a combination of magnetic sensors and impedance patches to detect changes in sensor positions, employing an electronic control unit to determine the cause of location changes and initiate correction algorithms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If magnetic localization systems are used to position catheters, then positioning capability is provided, but accuracy deteriorates due to magnetic field distortions from ferrous objects
Solution Approach 1:
The patent combines magnetic localization systems with impedance-based tracking systems into a hybrid system. The magnetic system provides positioning capability while the impedance system provides an alternative measurement method that is not affected by magnetic distortions. By merging both systems and comparing their measurements, the patent can detect and correct positioning errors caused by magnetic field distortions from ferrous objects.
Solution Approach 2:
The impedance-based tracking system acts as an intermediary that provides independent verification of catheter position. Since impedance measurement is not affected by magnetic field distortions, it serves as a mediator to detect when magnetic-based positioning becomes inaccurate due to ferrous objects, allowing for error correction without requiring direct removal of the harmful ferrous objects.
2Measurement precision
If hybrid magnetic and impedance tracking systems are used, then positioning accuracy is improved, but device complexity increases
Solution Approach 1:
The hybrid tracking system uses the same sensor infrastructure for multiple purposes: magnetic field sensing for primary positioning and impedance sensing for verification and distortion detection. The electronic control unit performs multiple functions including position calculation, distortion detection, and error correction using the same hardware components, thereby reducing the actual complexity increase despite having dual measurement capabilities.
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 system accurately distinguishes between magnetic field distortions and physical movements, thereby correcting catheter positioning errors and enhancing the precision of medical device localization within the body.
Implementation Method 1
magnetic localization systems have been developed that provide a location of the catheter within a well-known and controlled magnetic field... The externally-generated magnetic fields include precise magnetic gradients (field lines) that are sensed by the catheter (e.g., by elements such as coils) being located within the magnetic field.
Implementation Method 2
impedance localization systems have been developed that provide a location of the catheter within three pairs of electrodes using electrical currents
Implementation Method 3
The currents induced by the magnetic field(s) in the sensors are analyzed using algorithmic processes and used to determine the position of the catheter within the patient's body
Data Source
AI summary
A system for differentiating between magnetic field distortion and physical movement in a hybrid magnetic and impedance tracking system can comprise a first drive patch and a second drive patch configured to generate an electrical field within the body for locating an electrode on the medical device, a magnetic localization system configured to generate a magnetic field, a magnetic sensor configured to receive signals from the magnetic localization system, and an electronic control unit configured to receive location data from the impedance localization system and magnetic sensor location data from the magnetic localization system. The electronic control circuit can be configured to detect a location change of the magnetic sensor and use the drive patch location data and magnetic sensor location data to determine whether the detected location change of the magnetic sensor is caused by a magnetic field distortion or a physical movement of the magnetic sensor.