Korean J Radiol.  2004 Jun;5(2):121-127. 10.3348/kjr.2004.5.2.121.

Saline-Enhanced Hepatic Radiofrequency Ablation Using a Perfused-Cooled Electrode: Comparison of Dual Probe Bipolar Mode with Monopolar and Single Probe Bipolar Modes

• Lee JM
• Han JK
• Kim SH
• Lee JY
• Kim DJ
• Lee MW
• Cho GG
• Han CJ
• Choi BI

• KMID: 753992
• DOI: http://doi.org/10.3348/kjr.2004.5.2.121

Abstract

OBJECTIVE
To determine whether saline-enhanced dual probe bipolar radiofrequency ablation (RFA) using perfused-cooled electrodes shows better in-vitro efficiency than monopolar or single probe bipolar RFA in creating larger coagulation necrosis. MATERIALS AND METHODS: RF was applied to excised bovine livers in both bipolar and monopolar modes using a 200W generator (CC-3; Radionics) and the perfused-cooled electrodes for 10 mins. After placing single or double perfused-cooled electrodes in the explanted liver, 30 ablation zones were created at three different regimens: group A; saline-enhanced monopolar RFA, group B; saline-enhanced single probe bipolar RFA, and group C; saline-enhanced dual probe bipolar RFA. During RFA, we measured the tissue temperature at 15 mm from the electrode. The dimensions of the ablation zones and changes in the impedance currents and liver temperature during RFA were then compared between the groups. RESULTS: The mean current values were higher for monopolar mode (group A) than for the bipolar modes (groups B and C) : 1550+/-25 mA in group A, 764+/-189 mA in group B and 819+/-98 mA in group C (p < 0.05). The volume of RF-induced coagulation necrosis was greater in group C than in the other groups: 27.6+/-2.9 cm3 in group A, 23.7+/-3.8 cm3 in group B, and 34.2+/-5.1 cm3 in group C (p < 0.05). However, there was no significant difference between the short-axis diameter of the coagulation necrosis in the three groups: 3.1+/-0.8 cm, 2.9+/-1.2 cm and 4.0+/-1.3 cm in groups A, B and C, respectively (p > 0.05). The temperature at 15 mm from the electrode was higher in group C than in the other groups: 70+/-18 degrees C in group A, 59+/-23 degrees C in group B and 96+/-16 degrees C in group C (p < 0.05). CONCLUSION: Saline-enhanced bipolar RFA using dual perfused-cooled electrodes increases the dimension of the ablation zone more efficiently than monopolar RFA or single probe bipolar RFA.

Keyword

Liver, interventional procedures; Radiofrequency ablation; Experimental study

MeSH Terms

Animals
Catheter Ablation/*instrumentation
Cattle
Comparative Study
Electrocoagulation
In Vitro
Liver/pathology/*surgery
Necrosis
Sodium Chloride
Support, Non-U.S. Gov't

Figure

• 

  Fig. 1 Photograph of the electrode used for saline-enhanced monopolar mode (group A) with a 4-cm active tip (upper), the electrode used for dual probe bipolar mode (group C) with a 2-cm active tip (middle) and a single bipolar electrode used for single probe bipolar mode (group B) with two 2-cm uninsulated portions (bottom).

• 

  Fig. 2 A graph showing the changes in mean temperature at 15 mm from the electrode tips in each group during radiofrequency ablation: group A = hypertonic saline-enhanced monopolar RFA; group B = hypertonic saline-enhanced single probe bipolar RFA; group C = hypertonic saline-enhanced dual probe bipolar RFA.

• 

  Fig. 3 Comparison of radiofrequency-induced coagulation in the three groups. Note that the mean long-axis coagulation diameters were larger in group C than in the other groups A. Photograph of specimen from group A (hypertonic saline-enhanced monopolar RFA) B. Photograph of specimen from group B (hypertonic saline-enhanced single probe bipolar RFA) C. Photograph of specimen from group C (hypertonic saline-enhanced dual probe bipolar RFA)

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