Consideration on Estimating Subcutaneous Fat Thickness Using Electrical Bio-Impedance Method

We carried out the numerical analysis by finite difference method (FDM) in order to examine fat thickness estimation for applying electrical bio-impedance method. Recently, increase of obese subject becomes large social problem. For obese prevention, it is said that health care by appropriate exercise is necessary. For example, it seems to be useful for health care by knowing adhesion condition of the subcutaneous fat in the femoral region, because metabolism rate and exercise ability can be grasped. Electrical bio-impedance method which is one of fat measurement methods can be carried out by simple and inexpensive equipments. Then, we carried out the examination by numerical analysis in order to establish the technique for estimating subcutaneous fat thickness in the femoral region by application of electrical bio-impedance method. We carried out the FDM analysis for cylindrical multilayer model on the assumption of femoral region. Two current electrodes and two voltage electrodes were installed with the Wenner electrode layout or the dipole-dipole layout on the model surface. We examined the relation between the electrode interval and the apparent resistivity based on the measuring voltage, source current, and the electrode layout. The result of examination with both two type of electrode layout shows that the apparent resistivity increased with the increase of the fat thickness. And, the apparent resistivity took a maximal value. The electrode interval, as the apparent resistivity shows a maximal value, is different for different fat thickness. We consider that fat thickness estimation becomes possible using the value of electrode interval where apparent resistivity shows a maximal value