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Improving sensitivity in the deep regions of a volume conductor using electrical focused impedance methods

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06 set 2024
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Figure 1:

Schematic representation of the sensitive region on a transverse plane of a volume conductor for two orthogonal TPIMs (a, b) from which FIM-4 (c) is obtained. The current drive electrodes (red dots) and the potential electrodes (blue dots) are shown in the first two diagrams for the respective TPIM configurations [12].
Schematic representation of the sensitive region on a transverse plane of a volume conductor for two orthogonal TPIMs (a, b) from which FIM-4 (c) is obtained. The current drive electrodes (red dots) and the potential electrodes (blue dots) are shown in the first two diagrams for the respective TPIM configurations [12].

Figure 2:

(a) A 3D perspective of a rectangular phantom (33 cm × 26 cm × 12 cm) showing the placement of electrodes on the two opposite sides. (b) Cross sectional view showing schemes for 4-electrode configuration showing current and voltage electrodes: 1st step – measuring TPIM1 (left hand figure), 2nd step – measuring TPIM2 (right hand figure), changing the electrode connections indicated by I’ (current drive, red) and V’ (potential electrodes, black), respectively. FIM was obtained as an algebraic average of TPIM1 and TPIM2.
(a) A 3D perspective of a rectangular phantom (33 cm × 26 cm × 12 cm) showing the placement of electrodes on the two opposite sides. (b) Cross sectional view showing schemes for 4-electrode configuration showing current and voltage electrodes: 1st step – measuring TPIM1 (left hand figure), 2nd step – measuring TPIM2 (right hand figure), changing the electrode connections indicated by I’ (current drive, red) and V’ (potential electrodes, black), respectively. FIM was obtained as an algebraic average of TPIM1 and TPIM2.

Figure 3:

A cross-sectional view of the modelled phantom showing the points where the centers of the spherical objects were placed (black dots, with lettered names). Along the X-axis, AB = 3 cm, AC = 6.5 cm, AD = 13 cm, AE = 20.5 cm, AF = 28 cm, AG = 30 cm, and along the Y-axis, SQ = 2.1 cm, SP = 3.25 cm, SO = 6.5 cm and SE = 13 cm. Red dots show the positions of the electrodes.
A cross-sectional view of the modelled phantom showing the points where the centers of the spherical objects were placed (black dots, with lettered names). Along the X-axis, AB = 3 cm, AC = 6.5 cm, AD = 13 cm, AE = 20.5 cm, AF = 28 cm, AG = 30 cm, and along the Y-axis, SQ = 2.1 cm, SP = 3.25 cm, SO = 6.5 cm and SE = 13 cm. Red dots show the positions of the electrodes.

Figure 4:

Phantom with electrodes and the instrument for electrical impedance measurement (Maltron Bioscan 920-II) used for the experimental study.
Phantom with electrodes and the instrument for electrical impedance measurement (Maltron Bioscan 920-II) used for the experimental study.

Figure 5:

Simulation results of the percentage change of impedance for TPIM1, TPIM2, and FIM with a spherical insulator (a) and conductor (b) placed at different points along the width of the Phantom (Y-position). The same for the experimental phantom(c) with insulator and (d) conductor.
Simulation results of the percentage change of impedance for TPIM1, TPIM2, and FIM with a spherical insulator (a) and conductor (b) placed at different points along the width of the Phantom (Y-position). The same for the experimental phantom(c) with insulator and (d) conductor.

Figure 6:

Simulation results of the percentage change of impedance for TPIM1, TPIM2, and FIM with a spherical insulator (a) and conductor (b) placed at different points along the width of the Phantom (X-position). The same for the experimental phantom(c) with insulator and (d) conductor.
Simulation results of the percentage change of impedance for TPIM1, TPIM2, and FIM with a spherical insulator (a) and conductor (b) placed at different points along the width of the Phantom (X-position). The same for the experimental phantom(c) with insulator and (d) conductor.