Finite element analysis of electrical impedance myography in the rat hind limb

Abstract

Electrical impedance myography (EIM) is a form of muscle assessment based on the surface application of electrical current and measurement of the resulting voltages over a muscle group of interest. In order to better understand the effect of pathological change in muscle, EIM has recently been applied to the rat. In this study, a finite element model of EIM is presented for the rat hind limb which incorporates the detailed anatomy of the leg based on computerized tomographic imaging and conductivity and permittivity values obtained from the rat gastrocnemius muscle. In addition, the angular anisotropy of the biceps femoris muscle has been included. The model successfully predicts the recorded surface impedances measured with EIM.

Assessment of Optimized Electrode Configuration for Electrical Impedance Myography Using Genetic Algorithm via Finite Element Model

“…The muscle and tissue material properties were homogeneous throughout the model. For nonelectrode boundaries, the normal component of the electric current was assumed to be continuous [11]. Electrodes were modelled as potential surfaces, the boundaries of which had either the excitation or zero current, except for the ground electrode, the potential of which was fixed at zero volts [15].…”

“…In this study, to analyse the variation of EIM parameters in different condition, a finite element model of human upper arm was developed. Finite Element Method (FEM) has been established as an appropriate approach for analysis of nonsymmetrical shape like muscle tissue for assessing alternations of muscle in disease-induced changes through ElM [11, 12]. The normal tissue properties were obtained from published resources [13] and used in this FEM model.…”

“…The normal tissue properties were obtained from published resources [13] and used in this FEM model. The abnormal muscle electrical properties were obtained from sciatic crush data of rat studies [11, 14]. …”

Identifying least affected parameters in analyzing Electrical Impedance Myography with alteration in subcutaneous fat thickness via finite element model

“…Another non-muscular anatomic factor that severely impacts the ElM parameters is subcutaneous fat (SF) thickness [13]. [16]. Electrodes were modelled as potential surfaces the boundaries of which had either the excitation or zero current, except for the ground electrode, the potential of which was fixed at zero volts [9].…”

Influence of Different Geometric Representations of the Volume Conductor on Nerve Activation during Electrical Stimulation

“…Computer models have been implemented analytically and numerically to explain the generation, propagation, and responses to external stimuli of neural activities. Applications include muscle condition assessment by electrical impedance myography [ 1 ], understanding and interpretation of electromyogram recordings [ 2 , 3 ], electrical impedance tomography [ 4 ], and evaluation of antenna transmission within tissues for body-area network applications [ 5 ]. Moreover, simulations of the neurons' polarization and depolarization when responding to external stimuli have been developed, such as transcranial magnetic stimulation [ 6 ], spinal cord DC stimulation [ 7 ], and functional electrical stimulation (FES) [ 8 – 10 ].…”