Table 1.

Measured values of technical parameters and shapes of coagulation necrosis according to radiofrequency power application modes

Parameters	Group A Consecutive mode RFA (n = 20)	Group B Switching monopolar RFA (n = 20)	Group C Switching bipolar RFA (n = 20)	p-valuea	p-value A vs B	p-value A vs C	p-value B vs C
Technical parameters
Total delivered energy (kJ)	120.9 ± 24.5	114.2 ± 18.3	76.8 ± 14.3	<0.001	0.728	<0.001	<0.001
Delivered energy per minute	5.3 ± 1.1	6.5 ± 1.3	9.46 ± 1.4	<0.001	<0.001	0.006	<0.001
Average Watt	84 ± 17	158.7 ±  25.4	106.7 ± 19.9	<0.001	<0.001	0.006	<0.001
Impedance (W)	57.9 ± 7.2	62.7 ± 12.7	61.3 ± 11.9	0.394	1.000	0.550	1.000
Qualitative analysis of coagulation necrosis
Confluent necrosis	30% (6/20)	85% (17/20)	90% (18/20)	0.0002b
Round shape	0	3	8
Oval shape	6	14	10
Partial confluent necrosis	55% (11/20)	15% (3/20)	10% (2/20)
Clover shape	10	2	1
Maple leaf shape	1	1	1
Separated necrosis	15% (3/20)	0% (0/20)	0% (0/20)
Quantitative analysis of coagulation necrosis
Circularity (isometric ratio)	0.69 ± 0.12	0.82 ± 0.08	0.85 ± 0.08	<0.001	<0.001	<0.001	0.758
Dmin : Dmax ratio	0.67 ± 0.19	0.79 ± 0.15	0.86 ± 0.13	0.002	0.057	0.002	0.643

D_max, maximum diameter of the ablation zone; D_min, minimum diameter of the ablation zone; D_v, vertical diameter of the ablation zone; RFA, radiofrequency ablation.

Values are mean ± standard deviation.

^ap-values indicate the statistical difference among Groups A–C.

^bχ² test results indicating the difference between the three groups.