ECG R-Wave Detection in MRI Using Reference Signal Interference Removal
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Solution Overview
Problem
ECG measuring devices face challenges in reliably detecting R-waves in magnetic resonance scanners due to interference from changing magnetic fields and breath-holding, which can lead to incorrect triggering and image quality deterioration.
Innovation Solution
A method that involves measuring reference ECG and breathing signals in undisturbed environments, creating comparison rules based on these signals, and applying them to detect R-waves in ECG signals, regardless of the breathing position, using pattern recognition and signal processing techniques to enhance accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If ECG measuring is performed in a magnetic resonance scanner, then medical imaging synchronization is achieved, but interference from changing magnetic fields falsifies the ECG signal
Solution Approach 1:
The patent extracts and removes the harmful interference component from the ECG signal by comparing the signal acquired in the magnetic resonance scanner with a reference ECG signal acquired outside the scanner. The interference is identified as the difference between these signals and is subtracted to obtain a cleaned ECG signal suitable for R-wave detection.
Solution Approach 2:
The patent introduces a reference ECG signal as an intermediary element. This reference signal, acquired in an interference-free environment, serves as a mediator to identify and remove the magnetic field interference from the signal acquired inside the scanner, enabling accurate R-wave detection despite the harsh electromagnetic environment.
2Duration of action of stationary object
If R-wave detection is performed during breath-holding, then cardiac imaging synchronization is maintained, but increased R-wave amplitudes due to heart position shift make reliable detection difficult
Solution Approach 1:
The patent applies dynamic adaptation by adjusting the detection criteria for R-waves based on the detected breathing phase. During breath-holding, the system modifies the expected R-wave characteristics to account for the heart position shift, maintaining detection accuracy despite changes in signal morphology caused by the examination object's breathing state.
3Adaptability or versatility
If interference signals are present in the ECG signal, then magnetic resonance imaging can be performed, but incorrect R-wave interpretation leads to wrong triggering and image quality deterioration
Solution Approach 1:
The patent implements feedback by continuously monitoring the ECG signal quality and adjusting the interference removal and R-wave detection parameters based on the detected signal characteristics. The system uses the reference signal as a feedback mechanism to identify when interference is present and applies appropriate correction to maintain reliable R-wave detection throughout the imaging process.
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
This method allows for reliable detection of R-waves independent of breathing position, reducing interference and improving image quality by accurately identifying R-waves even in challenging conditions like magnetic resonance scanners and breath-holding.
Implementation Method 1
the total voltage of the electrical activity of the heart muscle fibers is typically measured as what is known as an ECG signal by way of at least two electrodes
Implementation Method 2
Magnetic fields that change over time generate interference voltages in accordance with Faraday's law of induction, and these are coupled as interference into the ECG signal recorded by the ECG electrodes
Data Source
AI summary
In a method for determining R-waves in an ECG signal, at least one reference ECG signal is measured, at least one reference breathing signal is measured, at least one reference R-wave is determined using the reference ECG signal and the reference breathing signal, at least one reference value is determined using the reference ECG signal and the reference breathing signal, at least one comparison rule is credited based on the at least one reference value, ECG signals are measured and breathing signals are measured in which R-waves are to be determined, the measured ECG signals and breathing signals are compared with the at least one reference value using the at least one comparison rule, and at least one R-wave is determined using the measured ECG signals and breathing signals.