MCG simulations with a realistic heart-torso model

Magnetocardiograms (MCGs) simulated high-resolution heart-torso model of an adult subject were compared with measured MCGs acquired from the same individual. An exact match of the measured and simulated MCGs was not found due to the uncertainties in tissue conductivities and cardiac source positions. However, general features of the measured MCGs were reasonably represented by the simulated data for most, but not all of the channels. This suggests that the model accounts for the most important mechanisms underlying the genesis of MCGs and may be useful for cardiac magnetic field modeling under normal and diseased states. MCGs were simulated with a realistic finite-element heart-torso model constructed from segmented magnetic resonance images with 19 different tissue types identified. A finite-element model was developed from the segmented images. The model consists of 2.51 million brick-shaped elements and 2.58 million nodes, and has a voxel resolution of 1.56/spl times/1.56/spl times/3 mm. Current distributions inside the torso and the magnetic fields and MCGs at the gradiometer coil locations were computed. MCGs were measured with a Philips twin Dewar first-order gradiometer SQUID-system consisting of 31 channels in one tank and 19 channels in the other.