Document Detail

Ex vivo experiment of saline-enhanced hepatic bipolar radiofrequency ablation with a perfused needle electrode: comparison with conventional monopolar and simultaneous monopolar modes.
MedLine Citation:
PMID:  15789259     Owner:  NLM     Status:  MEDLINE    
The purpose of this study was to validate the saline-enhanced bipolar radiofrequency ablation (RFA) technique using a perfused electrode to increase RF-created coagulation necrosis, to compare that technique with monopolar RFAs and to find appropriate concentrations and volumes of perfused NaCl solution for the bipolar RFA. A total of 90 ablations were performed in explanted bovine livers. In the initial experiments to determine appropriate conditions for bipolar RFA, we created five thermal ablation zones in each condition, with instillations of varied concentrations (0.9-36%) or injection rates (30 mL/hr-120 mL/hr) of NaCl solution. After placement of one or two 16-gauge open-perfused electrodes into bovine livers, the NaCl solution was instilled into the tissue through the electrode. In the second part of the study, 10 ablation zones were created using one or two perfused electrodes for each of five groups under different conditions: a conventional monopolar mode with 0.9% NaCl solution (group A) or with 6% NaCl solution (group B), a simultaneous monopolar mode with 6% NaCl solution (group C) and a bipolar mode with 6% NaCl solution (groups D and E). RF was applied to each electrode for 20 min in groups A, B, C, and E, or for 10 min in group D. During RFA, we measured the tissue temperature 15 mm from the electrode. The temperature changes during the RFA and the dimensions of the ablation zones were compared among the groups. Bipolar RFA created larger short-axis diameters of coagulation necrosis with 6% NaCl solution (35.8 +/- 15 mm) than with 0.9% NaCl solution (17 +/- 9.7 mm) (P < 0.05). However, concentrations of NaCl solution above 6% did not further increase the extent of coagulation necrosis. In addition, bipolar RFA with 6% NaCl solution instillation at a rate of 1.0 mL/min (37.9 +/- 5.4 mm) or 2.0 mL/min (35.6 +/- 9.3 mm) produced larger diameters at the mid-point between the electrodes of the ablated lesion than did 0.5 mL/min (25.8 +/- 9.3 mm) (P < 0.05). The bipolar mode showed a more rapid increase in temperature at the mid-point between the two probes, up to 60 degrees C, than did the monopolar modes (P < 0.05). In addition, the bipolar RFA (group E) treated for 20 min showed a larger value of the short-axis diameter than did the conventional or simultaneous monopolar modes (P < 0.05), and bipolar RFA (group D) treated for 10 min, showed similar results with conventional monopolar modes treated for 20 min (P > 0.05): 31.0 +/- 5.4 mm (group A); 28.8 +/- 3.8 mm (group B); 25.5 +/- 6.4 mm (group C); 32.6 +/- 4.2 mm (group D); 49.4 +/- 5.0 mm (group E). Bipolar RFA with instillation of 6% NaCl solution through an open perfusion system demonstrates better efficacy in creating a larger ablation zone than does conventional or simultaneous monopolar modes at the various times examined. Therefore, hypertonic saline-enhanced bipolar RFA seems to be a promising approach for treating larger liver tumors.
Jeong Min Lee; Se Hyung Kim; Joon Koo Han; Kyu Li Sohn; Byung Ihn Choi
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Publication Detail:
Type:  Comparative Study; Journal Article    
Journal Detail:
Title:  Cardiovascular and interventional radiology     Volume:  28     ISSN:  0174-1551     ISO Abbreviation:  Cardiovasc Intervent Radiol     Publication Date:    2005 May-Jun
Date Detail:
Created Date:  2005-06-03     Completed Date:  2005-09-01     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  8003538     Medline TA:  Cardiovasc Intervent Radiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  338-45     Citation Subset:  IM    
Department of Radiology, Seoul National University College of Medicine, Seoul, Korea. LEEJM@RADCOM.SNU.AC.KR
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MeSH Terms
Body Temperature / physiology
Catheter Ablation / instrumentation*,  methods
Electric Impedance
Equipment Design
Liver / pathology,  surgery*
Reproducibility of Results
Saline Solution, Hypertonic / administration & dosage,  therapeutic use*
Time Factors
Reg. No./Substance:
0/Saline Solution, Hypertonic

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