Catheter Motion Detection Using Variance Filtering of Respiratory Noise

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Solution Overview

Problem

Existing catheter position systems struggle to differentiate between deliberate motion caused by an operator and involuntary motion due to patient respiration or cardiac activity, leading to flawed motion compensation parameters.

Innovation Solution

A method and system using magnetic sensors to collect and process magnetic sensor samples, removing respiration motion frequency components, and calculating a baseline effective variance limit to detect deliberate catheter motion by comparing running variance to this limit.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If motion compensation is performed using periodic evaluation, then catheter position stability is improved, but measurement precision deteriorates when deliberate motion is present

Engineering Contradiction:

Improvecatheter position stabilityVSAvoidmotion compensation precision

Core Design Contradiction:

Stability of the object's compositionVSMeasurement precision

Solution Approach 1:

The system continuously monitors catheter position and compares it against baseline data to detect deliberate motion. When deliberate motion is detected through variance analysis, the system adjusts the periodic evaluation timing to avoid flawed data, thereby maintaining both position stability and measurement precision through feedback-driven adaptation.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system dynamically changes the parameter of evaluation timing based on detected motion patterns. By calculating running variance and comparing it to baseline variance, the system identifies when deliberate motion occurs and adjusts when periodic evaluations are performed, ensuring high precision motion compensation while maintaining overall position stability.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If periodic evaluation is performed continuously, then productivity is improved, but reliability deteriorates due to flawed data from deliberate motion

Engineering Contradiction:

Improvemotion compensation efficiencyVSAvoiddata quality

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The system performs preliminary detection of deliberate motion by continuously monitoring catheter position variance before conducting periodic evaluations. By identifying deliberate motion in advance through baseline comparison, the system prevents flawed data from being collected, ensuring high reliability while maintaining efficient continuous operation.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

When deliberate motion is detected through variance analysis, the system skips the periodic evaluation during that period to avoid collecting flawed data. This selective skipping maintains overall productivity by quickly identifying and bypassing contaminated evaluation windows while continuing efficient monitoring and evaluation during clean periods.

Inventive Principle:

Principle #21Skipping (Rushing through)

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

Accurately distinguishes between deliberate and involuntary catheter motion, ensuring accurate motion compensation parameters by filtering out respiration and cardiac-induced variations.

Implementation Method 1

magnetic field-based positioning system... one or more magnetic field detection coils coupled with a medical device... The generators provide a controlled low-strength AC magnetic field in the area of interest... The detection coils produce a respective signal indicative of one or more characteristics of the sensed field

Methodology Applied

Scientific EffectMagnetic field detection: Magnetic Field

Implementation Method 2

removing a respiration motion frequency component from the from the plurality of first magnetic sensor samples with a signal processing filter

Methodology Applied

Scientific EffectSignal filtering: Filter (electronic)

Data Source

PatentUS12496143B2Systems and methods for detecting catheter deliberate motion

Publication Date: 2025.12.16 ST JUDE MEDICAL CARDILOGY DIV INC

AI summary

According to some embodiments of the present disclosure, a method for detecting deliberate motion of a catheter positioned within a patient and including a magnetic sensor includes collecting a plurality of first magnetic sensor samples. The method includes measuring a sensor position P0 in 3D coordinates for each of the first magnetic sensor samples and measuring a sensor orientation for each of the first magnetic sensor samples. Measuring the sensor orientation includes generating a first vector (P0-P1) and generating a second vector (P0-P2) orthogonal to the first vector. The method includes removing a respiration motion frequency component from the from the plurality of first magnetic sensor samples with a signal processing filter. A running variance for each axis (x, y, z) of the P1 and P2 is computed. The method includes generating an output indicative of detected deliberate motion based on the computed running variance.