Estimation of extracellular volume by a two-frequency measurement.
An approach to determine intra- and extracellular conduction on the basis of Bode analysis is presented. Estimation of the ratio between intra- and extracellular conduction could be performed by phase measurement only, midrange in the bandwidth of interest. An important feature is that the relation between intra- and extracellular conduction can be continuously monitored by phase measurement and no curve fitting whatsoever is required. Based on a two-frequency measurement determining Re at 4 kHz and phi max at 64 kHz, it proved possible to estimate extracellular volume (ECV) in 23 patients. Reference values on ECV were determined by sodium bromide. The results show a good correlation (r = 0.90) with the reference method. The average error of ECV estimation was -3.6% (SD 8.4).
Goovaerts
H G
HG
Department of Clinical Physics and Informatics, University Hospital Vrije Universiteit, Amsterdam, The Netherlands.
Faes
T J
TJ
de Valk-de Roo
G W
GW
ten Bolscher
M
M
Netelenbosch
J C
JC
van der Vijgh
W J
WJ
Heethaar
R M
RM
D001823:Body Composition; D002118:Calcium / Q000378:metabolism; D004553:Electric Conductivity; D017097:Electric Impedance; D004958:Estradiol / Q000494:pharmacology; D005110:Extracellular Space / Q000502:physiology*; D005260:Female; D006801:Humans; D007408:Intestinal Absorption / Q000502:physiology; D008954:Models, Biological; D017698:Postmenopause
D004958:Estradiol; D002118:Calcium