Real-time extraction of tissue impedance model parameters for electrical impedance spectrometer.
This paper presents a new algorithm for real-time extraction of tissue electrical impedance model parameters from in vivo electrical impedance spectroscopic measurements. This algorithm was developed as a part of a system for muscle tissue ischemia measurements using electrical impedance spectroscopy. An iterative least square fitting method, biased with a priori knowledge of the impedance model was developed. It simultaneously uses both the real and imaginary impedance spectra to calculate tissue parameters R0, R infinity, alpha and tau. The algorithm was tested with simulated data, and during real-time in vivo ischemia experiments. Experimental results were achieved with standard deviations of sigma R0 = 0.80%, sigma R infinity = 0.84%, sigma alpha = 0.72%, and sigma tau = 1.26%. On a Pentium II based PC, the algorithm converges to within 0.1% of the results in 17 ms. The results show that the algorithm possesses excellent parameter extraction capabilities, repeatability, speed and noise rejection.
Kun
S
S
Worcester Polytechnic Institute, Biomedical Engineering Department, MA 01609, USA. skun@wpi.edu
Ristic
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B
Peura
R A
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Dunn
R M
RM
D000465:Algorithms; D000818:Animals; D017097:Electric Impedance; D007511:Ischemia / Q000175:diagnosis*; D018482:Muscle, Skeletal / Q000098:blood supply*; D011817:Rabbits; D012815:Signal Processing, Computer-Assisted; D013057:Spectrum Analysis / Q000379:methods