Intra-MRI Extraction of Diagnostic Electrocardiograms Using Carotidal Magnetohydrodynamic Voltages
AbstractThe electrocardiogram (ECG) is commonly utilized for patient monitoring during magnetic resonance imaging (MRI) despite known magnetohydrodynamic voltage (VMHD) overlays, which often eclipse the true sinus rhythm and render the signal to be non-diagnostic. This can complicate MRI gating and at-risk patient monitoring, causing alternative low-fidelity signals to become preferred. We aimed to develop a method of isolating the true sinus rhythm from VMHD in order to enable the use of high-fidelity ECGs during MRI procedures. Twelve-lead ECGs were acquired in two healthy volunteers (n = 2) in a 3T MRI scanner, while a secondary single lead monitor was positioned across the left common carotid artery to directly record VMHD while cancelling out the true sinus rhythm. Carotid MHD was used to adaptively train a least mean squares filter to update a 12-lead ECG VMHD template and produce: (1) clean 12-lead ECGs and (2) an accurate stroke volume (SV) estimate. The adaptive filtering method was shown to reduce VMHD in 12-lead ECGs. This was demonstrated by an average cross-correlation of 0.81 across all ECG leads calculated between filtered ECG taken inside the MRI scanner and the ECG taken outside the MRI scanner. Residual noise formed <5% of the R-wave amplitude. Additionally, the method required only a short training phase. A method to extract real sinus rhythm beats from intra-MRI 12-lead ECGs was presented and shown to provide accurate dynamic measurements of induced VMHD using flow in the carotid artery as a source of dynamic feedback. View Full-Text
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Gregory, T.S.; Wu, K.J.; Oshinski, J.N.; Tse, Z.T.H. Intra-MRI Extraction of Diagnostic Electrocardiograms Using Carotidal Magnetohydrodynamic Voltages. J. Imaging 2018, 4, 66.
Gregory TS, Wu KJ, Oshinski JN, Tse ZTH. Intra-MRI Extraction of Diagnostic Electrocardiograms Using Carotidal Magnetohydrodynamic Voltages. Journal of Imaging. 2018; 4(5):66.Chicago/Turabian Style
Gregory, T. S.; Wu, Kevin J.; Oshinski, John N.; Tse, Zion T.H. 2018. "Intra-MRI Extraction of Diagnostic Electrocardiograms Using Carotidal Magnetohydrodynamic Voltages." J. Imaging 4, no. 5: 66.
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