title: A new method for noninvasive measurement of multilayer tissue conductivity and structure using divided electrodes.
abstract: This paper outlines a new method for measuring multilayer tissue conductivity and structure by using divided electrodes, in which current electrodes are divided into several parts. Our purpose is to estimate the multilayer tissue structure and the conductivity distribution in a cross section of the local tissue by using bioresistance data measured noninvasively. The effect of the new method is assessed by computer simulations using a typical two-dimensional (2-D) model. In this paper, the conductivity distribution in the model is analyzed based on a finite difference method (FDM) and a steepest descent method (SDM). Simulation results show that the conductivity values of skin, fat, and muscle layers can be estimated with an error of less than 0.1%. When random noise at various levels is added to the measured resistance values, estimates of the conductivity values for skin, fat, and muscle layers are still reasonably precise: their root mean square errors are about 1.06%, 1.39%, and 1.61% for 10% noise. In a 2-D model, increasing the number of divided electrodes permits simultaneous estimates of tissue structure and conductivity distribution. Optimal configuration for divided electrodes is examined in terms of dividing pattern.
authors.affiliation: Laboratory of Biomedical Engineering, Institut de recherches cliniques de Montreal, 110 Avenue des Pins O, Montreal, QC, H2W 1R7, Canada. Xueli.Zhao@ICRM.qc.ca
authors.forename: Xueli
authors.initials: X
authors.lastname: Zhao
authors.forename: Y
authors.initials: Y
authors.lastname: Kinouchi
authors.forename: E
authors.initials: E
authors.lastname: Yasuno
authors.forename: D
authors.initials: D
authors.lastname: Gao
authors.forename: T
authors.initials: T
authors.lastname: Iritani
authors.forename: T
authors.initials: T
authors.lastname: Morimoto
authors.forename: M
authors.initials: M
authors.lastname: Takeuchi
mesh_terms: D000273:Adipose Tissue / Q000502:physiology*; D000465:Algorithms; D000818:Animals; D003198:Computer Simulation; D004553:Electric Conductivity; D004566:Electrodes; D006801:Humans; D008954:Models, Biological; D018482:Muscle, Skeletal / Q000502:physiology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012879:Skin Physiological Phenomena; D014054:Tomography / Q000379:methods*