Determination of the temperature-dependent electric conductivity of liver tissue ex vivo and in vivo: Importance for therapy planning for the radiofrequency ablation of liver tumours

Figures & data

Figure 1. (A) Measurement set-up with 4-electrode measurement probe and LCR measurement bridge; (B) 4-electrode measurement probe in detail.

Figure 2. Experimental set-up and measurement order of ex vivo examination in porcine liver.

Figure 3. Experimental set-up of in vivo examinations in perfused porcine liver.

Figure 4. Measurement curve of medians from 25 individual measurements from ex vivo porcine liver (grey points, changes during the heating phase; white points, changes during the cooling phase).

Table I.  Specific conductivity during the coagulation process (median with min/max is given in steps of 5°C).

Temperature°C	Specific conductivity (median of 25 measurements)
30	0.36 S/m (0.28; 0.47)
35	0.40 S/m (0.31; 0.51)
40	0.43 S/m (0.36; 0.57)
45	0.47 S/m (0.35; 0.61)
50	0.52 S/m (0.40; 0.66)
55	0.56 S/m (0.42; 0.69)
60	0.61 S/m (0.46; 0.73)
65	0.66 S/m (0.50; 0.70)
70	0.71 S/m (0.56; 0.84)
75	0.77 S/m (0.61; 0.89)
80	0.79 S/m (0.70; 0.87)
85	0.78 S/m (0.58; 0.87)
90	0.75 S/m (0.54; 0.86)

Table II.  Specific conductivity during the cooling process (median with min/max is given in steps of 5°C).

Temperature°C	Specific conductivity (median of 25 measurements)
90	0.62 S/m (0.51; 0.80)
85	0.58 S/m (0.48; 0.80)
80	0.54 S/m (0.46; 0.72)
75	0.52 S/m (0.43; 0.69)
70	0.50 S/m (0.41; 0.68)
65	0.47 S/m (0.39; 0.65)
60	0.46 S/m (0.37; 0.63)
55	0.44 S/m (0.36; 0.61)
50	0.42 S/m (0.34; 0.59)
45	0.40 S/m (0.32; 0.56)
40	0.38 S/m (0.31; 0.52)
35	0.36 S/m (0.30; 0.49)
30	0.35 S/m (0.28; 0.47)