Spatio-temporal analysis the results of solving the inverse problem of electrocardiography

The results of the development and testing an algorithm for the physiological interpretation the results of solving the inverse problem of electrocardiography are presented. The solution to the inverse problem of electrocardiography is the distributions of equivalent current sources on the quasi-epicardium, restored from the electric potentials created by the heart on the surface of the chest. The developed algorithms are based on the space-time analysis of the distributions of equivalent current sources on the quasi-epicardium. The development and testing of the algorithm was carried out using a simulation model of the electrical activity of the heart based on cellular automata. The efficiency of the algorithm has been demonstrated when simulating the electrical activity of the heart in normal conditions, as well as in the presence of pathological changes in the myocardium in the form of areas with delayed conduction of excitation.

Clinical Validation of the Champagne Algorithm for Evoked Response Source Localization in Magnetoencephalography

Magnetoencephalography (MEG) is a robust method for non-invasive functional brain mapping of sensory cortices due to its exceptional spatial and temporal resolution. The clinical standard for MEG source localization of functional landmarks from sensory evoked responses is the equivalent current dipole (ECD) localization algorithm, known to be sensitive to initialization, noise, and manual choice of the number of dipoles. Recently many automated and robust algorithms have been developed, including the Champagne algorithm, an empirical Bayesian algorithm, with powerful abilities for MEG source reconstruction and time course estimation (Wipf et al. 2010; Owen et al. 2012). Here, we evaluate automated Champagne performance in a clinical population of tumor patients where there was minimal failure in localizing sensory evoked responses using the clinical standard, ECD localization algorithm. MEG data of auditory evoked potentials and somatosensory evoked potentials from 21 brain tumor patients were analyzed using Champagne, and these results were compared with equivalent current dipole (ECD) fit. Across both somatosensory and auditory evoked field localization, we found there was a strong agreement between Champagne and ECD localizations in all cases. Given resolution of 8mm voxel size, peak source localizations from Champagne were below 10mm of ECD peak source localization. The Champagne algorithm provides a robust and automated alternative to manual ECD fits for clinical localization of sensory evoked potentials and can contribute to improved clinical MEG data processing workflows.