Assessment of Alterations in the Electrical Impedance of Muscle After Experimental Nerve Injury via Finite-Element Analysis

作者：Wang Lucy L; Ahad Mohammad; McEwan Alistair; Li Jia; Jafarpoor Mina; Rutkove Seward B^*

来源：IEEE Transactions on Biomedical Engineering, 2011, 58(6): 1585-1591.

DOI：10.1109/TBME.2011.2104957

• Element methods
• impedance
• muscle

The surface measurement of electrical impedance of muscle, incorporated as the technique of electrical impedance myography (EIM), provides a noninvasive approach for evaluating neuromuscular diseases, including amyotrophic lateral sclerosis. However, the relationship between alterations in surface impedance and the electrical properties of muscle remains uncertain. In order to investigate this further, a group of healthy adult rats, a group of rats two weeks postsciatic crush, and a group of animals six months postcrush underwent EIM of the gastrocnemius-soleus complex. The animals were then killed and the conductivity and permittivity of the extracted muscle measured. Finite-element models based on MRI data were then constructed for each group. The characteristic EIM parameter, 50 kHz phase (+/- standard error), obtained with surface impedance measurements was 17.3 degrees +/- 0.3 degrees for normal animals, 13.8 degrees +/- 0.7 degrees for acutely injured animals, and 16.1 degrees +/- 0.5 degrees for chronically injured animals. The models predicted parallel changes with phase values of 24.3 degrees, 18.8 degrees, and 21.2 degrees for the normal, acute, and chronic groups, respectively. Other multifrequency impedance parameters showed similar alterations. These results confirm that surface impedance measurements taken in conjunction with anatomical data and finite-element models may offer a noninvasive approach for assessing biophysical alterations in muscle in neuromuscular disease states.

• 出版日期2011-6