title: Switching bipolar hepatic radiofrequency ablation using internally cooled wet electrodes: comparison with consecutive monopolar and switching monopolar modes.
abstract: OBJECTIVE
  To evaluate whether switching bipolar radiofrequency ablation (SB-RFA) using three internally cooled wet (ICW) electrodes can induce coagulations >5 cm in porcine livers with better efficiency than consecutive monopolar (CM) or switching monopolar (SM) modes.
  
  
  METHODS
  A total of 60 coagulations were made in 15 in vivo porcine livers using three 17-gauge ICW electrodes and a multichannel radiofrequency (RF) generator. RF energy (approximately 200 W) was applied in CM mode (Group A, n = 20) for 24 min, SM mode for 12 min (Group B, n = 20) or switching bipolar (SB) mode for 12 min (Group C, n = 20) in in vivo porcine livers. Thereafter, the delivered RFA energy, as well as the shape and dimension of coagulations were compared among the groups.
  
  
  RESULTS
  Spherical- or oval-shaped ablations were created in 30% (6/20), 85% (17/20) and 90% (18/20) of coagulations in the CM, SM and SB groups, respectively (p = 0.003). SB-RFA created ablations >5 cm in minimum diameter (Dmin) in 65% (13/20) of porcine livers, whereas SM- or CM-RFA created ablations >5 cm in only 25% (5/20) and 20% (4/20) of porcine livers, respectively (p = 0.03). The mean Dmin of coagulations was significantly larger in Group C than in Groups A and B (5.1 ± 0.9, 3.9 ± 1.2 and 4.4 ± 1.0 cm, respectively, p = 0.002) at a lower delivered RF energy level (76.8 ± 14.3, 120.9 ± 24.5 and 114.2 ± 18.3 kJ, respectively, p < 0.001).
  
  
  CONCLUSIONS
  SB-RFA using three ICW electrodes can create coagulations >5 cm in diameter with better efficiency than do SM- or CM-RFA.
  
  
  CONCLUSIONS
  SB-RFA can create large, regular ablation zones with better time-energy efficiency than do CM- or SM-RFA.
authors: 1 Department of Radiology, Seoul National University Hospital, Seoul, Republic of Korea.
authors: J H
authors: JH
authors: Yoon
authors: J M
authors: JM
authors: Lee
authors: S
authors: S
authors: Woo
authors: E J
authors: EJ
authors: Hwang
authors: I
authors: I
authors: Hwang
authors: W
authors: W
authors: Choi
authors: J K
authors: JK
authors: Han
authors: B I
authors: BI
authors: Choi
mesh_terms: D000818:Animals; D017115:Catheter Ablation / Q000295:instrumentation*; D004566:Electrodes; D004867:Equipment Design; D008099:Liver / Q000601:surgery*; D023421:Models, Animal; D011846:Radio Waves; D013552:Swine