Katz Sagie, Zlochiver Sharon, Abboud Shimon
Department of Biomedical Engineering, Faculty of Engineering, Tel-Aviv University, Ramat-Aviv, Tel-Aviv, 69978, Israel.
Ann Biomed Eng. 2006 Aug;34(8):1332-42. doi: 10.1007/s10439-006-9146-0. Epub 2006 Jun 29.
In this study, the feasibility of using induced current bio-impedance technique as a method to determine and monitor bone mineral density (BMD) was theoretically evaluated using computerized simulation model. A 2D polar coordinates numerical solver was developed using the Finite Volume Method (FVM) in order to simulate the developed potentials over an axial CT cross section of a human thigh. Varying femur BMD were simulated by varying femur relative permittivity values. At the chosen excitation current of 1 ampere at a frequency of 20 kHz, the real component of the surface potential was found to be more sensitive to BMD variation than the imaginary component (3.9 microV g(-1) cm3 compared with 0.174 microV g(-1) cm3). The correlation between varying femur permittivities and the real component of the developed surface potential was found to be quadratic and influenced by the coil geometry and the measuring point location. Measurement sensitivity was improved either by taking the measuring point closer to the femur location or by minimizing the distance between the excitation coil and the femur. These results provide the basic principle that may enable a future use of bio-impedance technique for bone density evaluation and monitoring.
在本研究中，使用计算机模拟模型从理论上评估了利用感应电流生物阻抗技术作为测定和监测骨矿物质密度（BMD）方法的可行性。使用有限体积法（FVM）开发了二维极坐标数值求解器，以模拟人体大腿轴向CT横截面的感应电势。通过改变股骨相对介电常数来模拟不同的股骨骨密度。在选定的20 kHz频率、1安培的激励电流下，发现表面电势的实部对骨密度变化比虚部更敏感（分别为3.9 μV g⁻¹ cm³和0.174 μV g⁻¹ cm³）。发现不同的股骨介电常数与感应表面电势实部之间的相关性呈二次关系，并且受线圈几何形状和测量点位置的影响。通过将测量点移近股骨位置或最小化激励线圈与股骨之间的距离，可以提高测量灵敏度。这些结果提供了未来可能将生物阻抗技术用于骨密度评估和监测的基本原理。
