Bio-Impedance Sensor for Real-Time Artery Diameter Waveform Assessment

Figures

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  Figure 1. Resistivities for various human tissues in the region of interest as a function of frequency [43].

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  Figure 2. Schematic diagram of the four-electrode setup. A and B are the current electrodes, M and N are the measuring electrodes.

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  Figure 3. The mathematical model of artery in the region of interest.

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  Figure 4. The dependence of electrical impedance changes due to artery diameter change: (a) The forward problem; (b) the inverse problem.

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  Figure 5. The obtained data using Doppler US: (a) brachial blood velocity assessment during 5 cardio cycles; (b) the averaged blood velocity curve.

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  Figure 6. The electrode system prototype: (a) multichannel electrode system placement; (b) the layout scheme of the relative electrodes’ positions and channels in the region of interest.

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  Figure 7. The red blood cells’ orientation effect estimation; (a) the averaged and smooth arterial blood velocity curve; (b) blood share rate curve.

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  Figure 8. The blood resistivity change caused by red blood cells’ orientation effect.

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  Figure 9. The recording of the bio-impedance signal with the first and second derivative.

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  Figure 10. The resulting curves of diameter changing for four patients.