ABSTRACT
Analyses of electromagnetic fields play an important role in understanding electromagnetic phenomena in living bodies. Worldwide, several groups develop and distribute standard models of the human body,1,2 and these models benefit research into electromagnetic fields. However, the present methodology for developing these standard models imposes certain limitations on the scope and accuracy of these analyses. The models consist of multiple tissues or organs segmented from cross-sectional images of the body. Each tissue has specific permittivity and conductivity values. Each organ, such as the brain, is modeled as a uniform medium. The electric properties of actual organs and tissues, however, are not necessarily uniform because of a variety of substructures. Moreover, these standard models do not replicate the anatomy of an individual subject and are not applicable to subject-specific analyses. One solution to the aforementioned issues will be the development of new methodology for impedance
6.3.3.1 Principles 161 6.3.3.2 Experimental Results 162
6.3.4 Impedance Imaging Using RF Current 165 6.3.4.1 Principles 165 6.3.4.2 Experimental Results 167
6.3.5 Magnetic Resonance Electrical Impedance Tomography 167 6.4 Magnetic Resonance Imaging of Electric Currents 169
6.4.1 Changes in Magnetic Resonance Signals Resulting from the Magnetic Field 169
6.4.2 Sensitivity to a Weak Electric Current 170 6.4.2.1 Neuronal Current Dipole 170 6.4.2.2 Theoretical Evaluation of Sensitivity 171 6.4.2.3 Experimental Evaluation of Sensitivity 174
6.4.3 Animal Studies 174 6.4.3.1 Brain Slices 174 6.4.3.2 In Vivo Experiments 176
6.4.4 Human Studies 178 6.5 Summary and Future Prospects 180 References 181
imaging of living bodies. Imaging of electric impedance will enable us to determine both the local distribution of electric properties within an organ and the detailed anatomy of an individual subject.
