Annals of Biomedical Engineering

, Volume 42, Issue 12, pp 2480–2489 | Cite as

Left-Ventricular Mechanical Activation and Aortic-Arch Orientation Recovered from Magneto-Hydrodynamic Voltages Observed in 12-Lead ECGs Obtained Inside MRIs: A Feasibility Study

  • T. Stan Gregory
  • Ehud J. Schmidt
  • Shelley Hualei Zhang
  • Raymond Y. Kwong
  • William G. Stevenson
  • Jonathan R. Murrow
  • Zion Tsz Ho TseEmail author


To explore use of the Magnetohydrodynamic Voltage (VMHD), observed in intra-MRI 12-lead electrocardiograms (ECG), to indicate the timing of the onset of left-ventricular mechanical activation (LVMA) and the orientation of the aortic-arch (AAO). Blood flow through the aortic arch during systole, in the presence of the MRI magnetic field (B 0), generates VMHD. Since the magnitude and direction of VMHD are determined by the timing and directionality of blood flow relative to B 0, we hypothesized that clinically useful measures, LVMA and AAO, could be extracted from temporal and vectorial VMHD characteristics. VMHD signals were extracted from 12-lead ECG traces by comparing traces obtained inside and outside the MRI scanner. VMHD was converted into the Vectorcardiogram frame of reference. LVMA was quantified in 1 subject at 1.5T and 3 subjects at 3T, and the result compared to CINE MRI. AAO was inferred for 4 subjects at 3T and compared to anatomical imaging of the aortic arch orientation in the transverse plane. A < 10% error was observed in LVMA measurements, while a < 3° error was observed in aortic arch orientation measurements. The temporal and vectorial nature of VMHD is useful in estimating these clinically relevant parameters.


12-Lead Electrocardiogram Cardiac MRI High-field MRI ECG MHD Mechanical activation Orientation Magnetohydrodynamic 



Funding sources: NIH U41-RR019703, NIH R03 EB013873-01A1, SBIR-1 R43 HL110427-01.




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Copyright information

© Biomedical Engineering Society 2014

Authors and Affiliations

  • T. Stan Gregory
    • 1
  • Ehud J. Schmidt
    • 2
  • Shelley Hualei Zhang
    • 2
  • Raymond Y. Kwong
    • 2
  • William G. Stevenson
    • 2
  • Jonathan R. Murrow
    • 3
  • Zion Tsz Ho Tse
    • 1
    Email author
  1. 1.College of EngineeringThe University of GeorgiaAthensUSA
  2. 2.Cardiology and RadiologyBrigham and Women’s HospitalBostonUSA
  3. 3.GRU-UGA Medical PartnershipThe University of GeorgiaAthensUSA

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