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 Tse

Research output: Contribution to journalArticle

6 Scopus citations


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.

Original languageEnglish (US)
Pages (from-to)2480-2489
Number of pages10
JournalAnnals of Biomedical Engineering
Issue number12
Publication statusPublished - Nov 21 2014
Externally publishedYes



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

ASJC Scopus subject areas

  • Biomedical Engineering

Cite this