170 likes | 356 Views
A novel model for blood impedance for indirect viscosity measurement. Zu-yao Chang, Gerard C.M. Meijer and Gheorghe A.M. Pop Faculty of Electrical Engineering, Mathematics and Computer Science,. Soz 2004. Structure. Introduction Contents of Blood Measurement techniques Measurement setup
E N D
A novel model for blood impedance for indirect viscosity measurement Zu-yao Chang, Gerard C.M. Meijer and Gheorghe A.M. Pop Faculty of Electrical Engineering, Mathematics and Computer Science, Soz 2004.
Structure • Introduction • Contents of Blood • Measurement techniques • Measurement setup • Experimental results • Conventional Model • Novel Model • Conclusions Soz 2004.
Source: Centraal Bureau voor de Statistiek Introduction • Heart and arterial diseases death cause no 1.
Introduction • Higher viscosity higher risk of blood-clot forming • Good correlation between blood viscosity and blood impedance. Soz 2004.
Introduction Soz 2004.
Contents of Blood • Plasma (volume 55%) • Blood Cells (volume 45%) • Leukocytes (white blood cells) • Thrombocytes (platelets) • Erythrocytes (red blood cells) Soz 2004.
Zpol Measurement technique • Two-electrode measurement technique • Four-electrode measurement technique Soz 2004.
HP4192A Vosc LabVIEW measurement circuit GainPhaseanalyzer Measurementcell Measurement circuit measurement cell GainG, Phase Impedance of Blood Mathematicalcalculations Labview |Z|, Measurement setup(4-electrodes) Z.Chang, 2003.
Nyquist Plot Polarization effects Blood Dielectric Properties of water Ht=45% T=24C Experimental results Soz 2004.
Conventional Model • Resistor Rp: plasma resistance with non-conducting blood cells. Rp • Capacitor Cm: cell-membrane capacitance. Ri Cm • Resistor Ri: interior cell-resistance. Where is the dielectric capacitance of water ? Soz 2004.
Nyquist plot of four-electrodes measurement Blood, Ht=45%, T=24ºC conv. model <1.2 MHz conventional model full freq. range Conventional Model Soz 2004.
Nyquist plot of two-electrodes measurement Cliq Blood, Ht=45%, T=24ºC Improved model total freq. fit Conventional Model Soz 2004.
Resistor Rp: plasma resistance with non-conducting blood cells. Cliq • Constant-Phase element CCPE_m: cell-membrane capacitance. Rp Ri CCPE_m Novel Model • Resistor Ri: interior cell-resistance. • CapacitorCliq: dielectric capacitance. Soz 2004.
Nyquist plot of four-electrodes measurement novel model Blood, Ht=45%, T=24ºC Conv. model, 3pnt Conventional model, all Novel Model Soz 2004.
Nyquist plot of two-electrodes measurement novel model Blood, Ht=45%, T=24ºC Conventional model with Cliq Novel Model Soz 2004.
Conclusions • It is possible to predict blood viscosity via blood impedance. • The validity of the early model of blood impedance is limited. • A novel model of blood impedance is found and its validity verified until 100MHz. Soz 2004.
Questions ? Soz 2004.