title: Real-time extraction of tissue impedance model parameters for electrical impedance spectrometer.
abstract: 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.
authors.affiliation: Worcester Polytechnic Institute, Biomedical Engineering Department, MA 01609, USA. skun@wpi.edu
authors.forename: S
authors.initials: S
authors.lastname: Kun
authors.forename: B
authors.initials: B
authors.lastname: Ristic
authors.forename: R A
authors.initials: RA
authors.lastname: Peura
authors.forename: R M
authors.initials: RM
authors.lastname: Dunn
mesh_terms: 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