Figure 1
Electric field distribution of to spheres with opposite charges Q (red) and -Q (blue). The measurement electrodes (green) are distanced by L. Background tissue (σba = 0) is assumed.
Figure 2
Electric field distribution by applying the voltages -V0 (red) on a sphere and on a spare charge plate (blue). The measurement electrodes (green) are distanced by L. Muscle tissue (σm) with a thickness of b and background tissue (σba) are modeled.
Figure 3
Left: electric field distribution of the injection at the outer electrodes with distance d. Middle: electric field distribution of the injection at the inner electrodes with distance L. Right: electric field distribution considering both the injection and the measurement field according to lead field theory.
Figure 4
Left: five cylindrical glass containers representing simplistic volumes to test the measurement system and calculation methods. 1: radius 13.3 mm, 2: radius 17.5 mm, 3: radius 32.8 mm, 4: radius 38.6 mm, 5: radius 50.4 mm. Right: close-up on the measurement catheter and a possible cascaded measurement configuration.
Figure 5
a) Left ventricular in-vitro phantoms made from silicone (left: carbon, right: pure), b) C-arm with manual test bench to measure phantom dimension, c) Cross-sectional areas obtained from CT measurements at the center electrode pair, adapted from [32].
Figure 6
Estimated radii using the classical Wei, the plate, and the lead ACM compared to the known radii of the cylinders (Data). Left: conductivity of saline solution σ1 = 1.69 S/m, right: conductivity of saline solution σ2 = 0.62 S/m.
Figure 7
Estimated radii by the ACMs (Wei, Plate, Lead) obtained from the conductances measured inside the in-vitro phantoms compared to reference radii (Data). Left: insulating phantom of pure silicone, right: silicone phantom enriched with carbon.
Table 1
Measured volumes inside the silicone ventricle from CT measurements. Cross-sectional areas obtained between the center electrode pair. Estimated equivalent center radius.
| Step | Volume (mL) | Area (mm2) | Radius (mm) |
|---|---|---|---|
| 1 | 117.90 | 1248.84 | 19.94 |
| 2 | 107.12 | 1022.55 | 18.04 |
| 3 | 97.96 | 855.50 | 16.50 |
| 4 | 87.20 | 683.15 | 14.75 |
| 5 | 76.84 | 506.83 | 12.70 |
| 6 | 69.46 | 401.12 | 11.30 |