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An enhanced frequency dependent subtraction algorithm for removal of cardiac interference from fMEG by using minimum
Neslihan Bisgin1, James D Wilson2, Hari Eswaran3
1Systems Engineering, University of Arkansas at Little Rock, Little Rock, AR, USA.
Journal of Neuroscience Methods
|February 15, 2020
Summary
A new method, SUBTRwMNPO, effectively removes maternal and fetal cardiac interference from fetal magnetoencephalography, improving evoked response detection. This enhanced technique ensures cleaner fetal brain signal analysis.
Area of Science:
- Biophysics
- Biomedical Engineering
- Neuroscience
Background:
- Maternal and fetal magnetocardiography (mMCG and fMCG) interfere with fetal magnetoencephalography (fMEG).
- Existing SUBTR methods struggle with cardiac residual noise when reference channels contain significant fMCG components.
- This noise degrades fetal evoked response (fER) detection.
Purpose of the Study:
- To develop an enhanced subtraction method for removing cardiac interference from fMEG.
- To improve the detection of fetal evoked responses (fER) by reducing noise.
Main Methods:
- Developed SUBTR with minimum norm projection operator (SUBTRwMNPO) using covariance-based MNPO.
- Extracted mMCG and fMCG signals using MNPO.
- Subtracted extracted cardiac signals in the frequency domain from raw data to isolate fER.
Main Results:
- SUBTRwMNPO demonstrated near-total attenuation of cardiac interference across 87 datasets.
- Resulted in significantly cleaner fetal evoked response (fER) signals.
- Outperformed standard SUBTR, especially in datasets with residual cardiac noise.
Conclusions:
- SUBTRwMNPO effectively removes cardiac interference regardless of signal space orientation.
- The method improves fER detection by providing cleaner signals.
- Applicable even without prior knowledge of fetal head location.
Keywords:
Fetal magnetocardiography (fMCG)Fetal magnetoencephalography (fMEG)Frequency dependent subtraction algorithm (SUBTR)Frequency dependent subtraction with minimum norm projection operator (SUBTRwMNPO)Maternal magnetocardiography (mMCG)Minimum norm projection operator (MNPO)
