CT findings after radiofrequency ablation in rabbit livers: comparison of internally cooled electrodes, perfusion electrodes, and internally cooled perfusion electrodes.
OBJECTIVE
To compare the computed tomography (CT) findings of radiofrequency (RF) ablation of rabbit livers with the use of internally cooled electrodes, perfusion electrodes, and internally cooled perfusion (ICP) electrodes.


METHODS
RF ablation zones were created in 24 rabbit livers in vivo in three groups, each treated at 30 W for 30 minutes with an electrode with a 1-cm active portion: one group was treated with an internally cooled electrode (group A), one with a perfusion electrode (group B), and one with an ICP electrode (group C). In the latter two groups, 0.9% saline solution mixed with contrast medium (9:1 ratio) was infused at a rate of 1 mL/min. Immediate CT images were ascertained in all groups and follow-up CT was performed in the latter two groups. CT findings of the RF ablation zone and surrounding liver parenchyma were evaluated and compared among groups.


RESULTS
On immediate unenhanced CT, infused contrast medium was noted in the center of the ablation zone without extravasation. Marginal linear or tubular low densities of the RF ablation zone were noted only in groups B (n=4) and C (n=3). Liver infarction was more frequently noted in groups B (n=5) and C (n=7) than in group A (n=3). Periportal tracking was noted more frequently in groups B (n=7) and C (n=8) than in group A (n=1). Pericaval or perihepatic tracking was noted only in groups B (n=3) and C (n=3). Extensive portal venous gas was noted in one animal in group C.


CONCLUSIONS
On CT, RF ablation with the perfusion or ICP electrode seemed to show more severe surrounding parenchymal changes than RF ablation with an internally cooled electrode.
Kim
Seung Kwon
SK
Deparment of Radiology, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, 180 Pyung-Dong, Jongro-Ku, Seoul 110-746, South Korea. radi@lycos.co.kr
Gu
Myung Seo
MS
Hong
Hyun Pyo
HP
Choi
Dongil
D
Chae
Seoung Wan
SW
D000818:Animals; D017115:Catheter Ablation / Q000295:instrumentation* / Q000379:methods; D003080:Cold Temperature; D004566:Electrodes; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008099:Liver / Q000000981:diagnostic imaging*; D008297:Male; D010477:Perfusion / Q000295:instrumentation* / Q000379:methods; D011817:Rabbits; D014057:Tomography, X-Ray Computed / Q000379:methods*