Suppression of MHD artifacts on single channel ECG during cardiac MRI

doi:10.1109/TENCON.2009.5396121

Proceedings Article•DOI•

Suppression of MHD artifacts on single channel ECG during cardiac MRI

Bhargav Bhatt¹, M. Ramasubba Reddy¹•Institutions (1)

01 Nov 2009-pp 1-4

TL;DR: A new signal processing method for suppression of Magnetohydrodynamic artifacts on single channel Electrocardiogram (ECG) during cardiac Magnetic Resonance Imaging (MRI) is proposed and the singular value decomposition (SVD) is performed on data in time-frequency domain to separate two signal components.

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Abstract: In this paper, a new signal processing method for suppression of Magnetohydrodynamic (MHD) artifacts on single channel Electrocardiogram (ECG) during cardiac Magnetic Resonance Imaging (MRI) is proposed. The singular value decomposition (SVD) is performed on data in time-frequency domain to separate two signal components. The performance of the method is evaluated using simulated signals for different heart rate variations and MR system dependent parameters such as, magnetic field strength and sampling frequency. In future, the performance of the method is to be studied on real signals acquired during the MRI scan.

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Journal Article•DOI•

A dynamical model for generating synthetic electrocardiogram signals

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Patrick E. McSharry¹, Gari D. Clifford¹, Lionel Tarassenko¹, Leonard A. Smith²•Institutions (2)

University of Oxford¹, London School of Economics and Political Science²

20 Mar 2003-IEEE Transactions on Biomedical Engineering

TL;DR: A dynamical model based on three coupled ordinary differential equations is introduced which is capable of generating realistic synthetic electrocardiogram (ECG) signals and may be employed to assess biomedical signal processing techniques which are used to compute clinical statistics from the ECG.

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Abstract: A dynamical model based on three coupled ordinary differential equations is introduced which is capable of generating realistic synthetic electrocardiogram (ECG) signals. The operator can specify the mean and standard deviation of the heart rate, the morphology of the PQRST cycle, and the power spectrum of the RR tachogram. In particular, both respiratory sinus arrhythmia at the high frequencies (HFs) and Mayer waves at the low frequencies (LFs) together with the LF/HF ratio are incorporated in the model. Much of the beat-to-beat variation in morphology and timing of the human ECG, including QT dispersion and R-peak amplitude modulation are shown to result. This model may be employed to assess biomedical signal processing techniques which are used to compute clinical statistics from the ECG.

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1,103 citations

"Suppression of MHD artifacts on sin..." refers methods in this paper

...MHD signals thus generated, is mixed with ECG signals given by ecgsyn [7] to obtain ECG, corrupted with MHD artifacts....
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Journal Article•DOI•

Observation of blood flow E.M.F. in externally applied strong magnetic field by surface electrodes

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Tatsuo Togawa¹, Osamu Okai¹, Masamitsu Oshima¹•Institutions (1)

University of Tokyo¹

01 Mar 1967-Medical & Biological Engineering & Computing

77 citations

"Suppression of MHD artifacts on sin..." refers background in this paper

...It works well for the magnetic field strength commonly used during MRI....
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...The dependency of MHD signal on heart rate is experimentally studied during cardiac stress test MRI by Fischer et al. [2]....
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...The MHD voltages are generated across the wall of the large blood vessels and can be observed with ECG signal recorded from body surface, during the MRI [1]....
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...The method may fail if patient heart rate changes significantly during the MRI....
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...Another method of MHD signal extraction described by Nijm et al. [3], used the subtraction of mean ECG beat generated with the subject outside the MRI bore from the mean beat generated with the subject inside the MRI bore....
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Proceedings Article•DOI•

Blind separation of fetal ECG from single mixture using SVD and ICA

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Ping Gao¹, Ee-Chien Chang, Lonce Wyse•Institutions (1)

National University of Singapore¹

15 Dec 2003

TL;DR: A novel blind-source separation method to extract fetal ECG from a single-channel signal measured on the abdomen of the mother by applying singular value decomposition on the spectrogram, followed by an iterated application of independent component analysis on the principle components.

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Abstract: In this paper, we propose a novel blind-source separation method to extract fetal ECG from a single-channel signal measured on the abdomen of the mother. The signal is a mixture of the fetal ECG, the maternal ECG and noise. The key idea is to project the signal into higher dimensions, and then use an assumption of statistical independence between the components to separate them from the mixtures. This is achieved by applying singular value decomposition (SVD) on the spectrogram, followed by an iterated application of independent component analysis (ICA) on the principle components. The SVD contributes to the separability of each component and the ICA contributes to the independence of the two components. We further refine and adapt the above general idea to ECG by exploiting a-prior knowledge of the maternal ECG frequency distribution and other characteristics of ECG. Experimental studies show that the proposed method is more accurate than using SVD only. Because our method does not exploit extensive domain knowledge of the ECGs, the idea of combining SVD and ICA in this way can be applied to other blind separation problems.

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77 citations

"Suppression of MHD artifacts on sin..." refers methods in this paper

...By transforming the single channel ECG to higher dimension, the multi channel technique can be employed [8]....
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Journal Article•DOI•

Extraction of the magnetohydrodynamic blood flow potential from the surface electrocardiogram in magnetic resonance imaging

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Grace M. Nijm¹, Steven Swiryn¹, Andrew C. Larson¹, Alan V. Sahakian¹•Institutions (1)

Northwestern University¹

01 Feb 2008-Medical & Biological Engineering & Computing

TL;DR: The magnetohydrodynamic effect generates voltages related to blood flow, which are superimposed on the electrocardiogram (ECG) used for gating during cardiac magnetic resonance imaging (MRI).

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Abstract: The magnetohydrodynamic effect generates voltages related to blood flow, which are superimposed on the electrocardiogram (ECG) used for gating during cardiac magnetic resonance imaging (MRI). A method is presented for extracting the magnetohydrodynamic signal from the ECG. The extracted magnetohydrodynamic blood flow potential may be physiologically meaningful due to its relationship to blood flow. Removal of the magnetohydrodynamic voltages from the ECG can potentially lead to improved gating and diagnostically useful ECGs.

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49 citations

"Suppression of MHD artifacts on sin..." refers background or methods in this paper

...[3], used the subtraction of mean ECG beat generated with the subject outside the MRI bore from the mean beat generated with the subject inside the MRI bore....
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...From the experimental studies of these artifacts it is reported that the aortic blood flow can be considered as main contributor in the MHD signal generation [2, 3]....
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Proceedings Article•DOI•

Alterations in human ECG due to the MagnetoHydroDynamic effect: A method for accurate R peak detection in the presence of high MHD artifacts

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Dima Abi-Abdallah¹, Vincent Robin¹, Agnès Drochon¹, Odette Fokapu¹•Institutions (1)

University of Technology of Compiègne¹

22 Oct 2007

TL;DR: In this paper, the MHD induced alterations of human ECG signals recorded in a 1.5 Tesla steady magnetic field are inspected and a primary characterization of the induced changes using time and frequency domain analysis is established.

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Abstract: Blood flow in high static magnetic fields induces elevated voltages that contaminate the ECG signal which is recorded simultaneously during MRI scans for synchronization purposes. This is known as the magnetohydrodynamic (MHD) effect, it increases the amplitude of the T wave, thus hindering correct R peak detection. In this paper, we inspect the MHD induced alterations of human ECG signals recorded in a 1.5 Tesla steady magnetic field and establish a primary characterization of the induced changes using time and frequency domain analysis. We also reexamine our previously developed real time algorithm for MRI cardiac gating [1] and determine that, with a minor modification, this algorithm is capable of achieving perfect detection even in the presence of strong MHD artifacts.

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36 citations

"Suppression of MHD artifacts on sin..." refers background in this paper

...[2, 4] shows that it mainly disturbs the ST segment and T-wave of the ECG and its frequency content lies in 1-4 Hz range....
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Suppression of MHD artifacts on single channel ECG during cardiac MRI

References

"Suppression of MHD artifacts on sin..." refers methods in this paper

"Suppression of MHD artifacts on sin..." refers background in this paper

"Suppression of MHD artifacts on sin..." refers methods in this paper

"Suppression of MHD artifacts on sin..." refers background or methods in this paper

"Suppression of MHD artifacts on sin..." refers background in this paper

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