Optimization of Wet Radiofrequency Ablation Using a Perfused-Cooled Electrode: A Comparative Study in Ex Vivo Bovine Livers
Korean Journal of Radiology
;
: 250-257, 2004.
Article
in English
| WPRIM
| ID: wpr-45950
ABSTRACT
OBJECTIVE:
To determine the optimized protocol for wet monopolar radiofrequency ablation (RFA) using a perfused-cooled electrode to induce coagulation necrosis in the ex vivo bovine liver. MATER ANDMETHODS:
Radiofrequency was applied to excised bovine livers in a monopolar mode using a 200W generator with an internally cooled electrode (groups A and B) or a perfused-cooled electrode (groups C, D, E, and F) at maximum power (150-200 W) for 10 minutes. A total of 60 ablation zones were created with six different regimens group A - dry RFA using intra-electrode cooling; group B - dry RFA using intra-electrode cooling and a pulsing algorithm; group C - wet RFA using only interstitial hypertonic saline (HS) infusion; group D - wet RFA using interstitial HS infusion and a pulsing algorithm; group E - wet RFA using interstitial HS infusion and intra-electrode cooling; and group F - wet RFA using interstitial HS infusion, intra-electrode cooling and a pulsing algorithm. In groups C, D, E, and F, RFA was performed with the infusion of 6% HS through the perfused cooled electrode at a rate of 2 mL/minute. During RFA, we measured the tissue temperature at a distance of 15 mm from the electrode. The dimensions of the ablation zones and the changes in impedance, currents, and liver temperature during RFA were compared between these six groups.RESULTS:
During RFA, the mean tissue impedances in groups A (243+/-88 omega) and C (252.5+/-108 omega) were significantly higher than those in groups B (85+/-18.7 omega), D (108.2+/-85 omega), E (70.0+/-16.3 omega), and F (66.5+/-7 omega) (p < 0.05). The mean currents in groups E and F were significantly higher than those in groups B and D, which were significantly higher than those in groups A and C (p < 0.05) 520+/-425 mA in group A, 1163+/-34 mA in group B, 652.5+/-418 mA in group C, 842.5+/-773 mA in group D, 1665+/-295 mA in group E, and 1830+/-109 mA in group F. The mean volumes of the ablation regions in groups E and F were significantly larger than those in the other groups (p < 0.05) 17.7+/-5.6 cm3 in group A, 34.5+/-3.0 cm3 in group B, 20.2+/-15.6 cm3 in group C, 36.1+/-19.5 cm3 in group D, 68.1+/-12.4 cm3 in group E, and 79.5+/-31 cm3 in group F. The final tissue temperatures at a distance of 15 mm from the electrode were higher in groups E and F than those in groups A, C, and D (p < 0.05) 50+/-7.5 degreesC in group A, 66+/-13.6 degreesC in group B, 60+/-13.4 degreesC in group C, 61+/-12.7 degreesC in group D, 78+/-14.2 degreesC in group E, and 79+/-12.0 degreesC in group F.CONCLUSION:
Wet monopolar RFA, using intra-electrode cooling and interstitial saline infusion, showed better performance in creating a large ablation zone than either dry RFA or wet RFA without intra-electrode cooling.
Full text:
Available
Index:
WPRIM (Western Pacific)
Main subject:
Perfusion
/
Saline Solution, Hypertonic
/
Body Temperature
/
Electric Impedance
/
Catheter Ablation
/
Disease Models, Animal
/
Electrodes, Implanted
/
Equipment Design
/
Liver
/
Necrosis
Limits:
Animals
Language:
English
Journal:
Korean Journal of Radiology
Year:
2004
Type:
Article
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