Quantification of cardiac magnetic field orientation

Abstract

Abstract The aim of this work was to compare three methods of determining cardiac magnetic field map orientation in the diagnosis of coronary artery disease (CAD). In 27 healthy subjects and 13 CAD patients, magnetocardiograms were registered at rest using a 61-channel biomagnetometer. Orientation was determined during QT interval using: 1) locations of centers-of-gravity of the positive and negative magnetic field strength values, 2) locations of the field extrema values and 3) the direction of the maximum field gradient. For each method, values of the healthy subjects determined normal orientation and the number of deviations from the normal values per subject was used to quantify the ability of each approach to discriminate between healthy and CAD subjects. The course of orientation was similar for all methods. The receiver-operating characteristic showed the best discrimination of CAD patients for the center-of-gravity approach (area-under-the-curve = 83%), followed by the gradient (81%) and the extrema method (75%). The results suggest that the extrema method is the least suitable of these approaches to clarify the potential of MCG in the noninvasive diagnosis of CAD.