Limits...
Combined radiofrequency ablation and acetic acid hypertonic saline solution instillation: an in vivo study of rabbit liver.

Lee JM, Kim YK, Kim SW, Han JK, Kim SH, Choi BI - Korean J Radiol (2004 Jan-Mar)

Bottom Line: All procedures are technically successful.With instillation of 15% AHS solution, a marked decrease of tissue impedance (24.5+/-15.6 ohm ) and an increase of current (250 mA) occurred as compared to RFA alone.A low concentration of AHS (15%) showed similar effects in increasing the extent of RF-induced coagulation, but there were less side effects as compared to the high concentration of AHS.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, Seoul National University College of Medicine, Seoul, Korea. leejm@radcom.snu.ac.kr

ABSTRACT

Objective: We wanted to determine whether combined radiofrequency ablation (RFA) and acetic acid-hypertonic saline solution (AHS) instillation can increase the extent of thermally mediated coagulation in in vivo rabbit liver tissue. We also wished to determine the optimal concentration of the solution in order to maximize its effect on extent of the RFA-induced coagulation.

Materials and methods: Forty thermal ablation zones were produced in 40 rabbits by using a 17-gauge internally cooled electrode with a 1-cm active tip under ultrasound guidance. The rabbits were assigned to one of four groups: group A: RFA alone (n=10); group B: RFA with 50% AHS instillation (n=10); group C: RFA with 25% AHS instillation (n=10); group D: RFA with 15% AHS instillation (n=10). A range of acetic acid concentrations diluted in 36% NaCl to a total volume of 1 mL were instilled into the liver before RFA. The RF energy (30W) was applied for three minutes. After RFA, in each group, the maximum diameters of the thermal ablation zones in the gross specimens were compared. Technical success and the complications that arose were evaluated by CT and on the basis of autopsy findings.

Results: All procedures are technically successful. There were six procedure related complications (6/40; 15%): two localized perihepatic hematomas and four chemical peritonitis. The incidence of chemical peritonitis was highest for group B with the 50% AHS solution instillation (30%). With instillation of 15% AHS solution, a marked decrease of tissue impedance (24.5+/-15.6 ohm ) and an increase of current (250 mA) occurred as compared to RFA alone. With instillation of the solutions before RFA (group B, C and D), this produced a greater mean diameter of coagulation necrosis than the diameters for rabbits not instilled with the solution (group A) (p < 0.05). However, there was no significant difference between group B, C, and D.

Conclusion: Combined AHS instillation and RFA can increase the dimension of coagulation necrosis in the liver with a single application. A low concentration of AHS (15%) showed similar effects in increasing the extent of RF-induced coagulation, but there were less side effects as compared to the high concentration of AHS.

Show MeSH

Related in: MedlinePlus

Cut Sections of gross specimens in the four groups. In groups B, C, and D, the combined radiofrequency ablations with instillation of the acetic acid-hypertonic saline solutions produced greater ablation zones than that does radiofrequency alone (group A).A. Gross specimen of a group A (radiofrequency ablation only) rabbit shows a round pale-discolored area (arrow) in the liver.B. Gross specimen of a group B (radiofrequency ablation with 50% acetic acid instillation) rabbit shows an oval shaped discolored coagulation zone (arrows) and thrombosis (arrowheads) of small vessels within the zone.C. Gross specimen of a group C (radiofrequency ablation with 25% acetic acid instillation) rabbit shows greater area of the ablation zone (arrow) than those of groups A (A) and B (B).D. Gross specimen of a group D (radiofrequency ablation with 15% acetic acid instillation) rabbit shows a similar appearance with the ablation zone to group C. Note that the thrombosis of small vessels (arrowheads) are seen in the coagulation area (arrow).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC2698111&req=5

Figure 1: Cut Sections of gross specimens in the four groups. In groups B, C, and D, the combined radiofrequency ablations with instillation of the acetic acid-hypertonic saline solutions produced greater ablation zones than that does radiofrequency alone (group A).A. Gross specimen of a group A (radiofrequency ablation only) rabbit shows a round pale-discolored area (arrow) in the liver.B. Gross specimen of a group B (radiofrequency ablation with 50% acetic acid instillation) rabbit shows an oval shaped discolored coagulation zone (arrows) and thrombosis (arrowheads) of small vessels within the zone.C. Gross specimen of a group C (radiofrequency ablation with 25% acetic acid instillation) rabbit shows greater area of the ablation zone (arrow) than those of groups A (A) and B (B).D. Gross specimen of a group D (radiofrequency ablation with 15% acetic acid instillation) rabbit shows a similar appearance with the ablation zone to group C. Note that the thrombosis of small vessels (arrowheads) are seen in the coagulation area (arrow).

Mentions: The RFA was technically successful in all test conditions. There were no deaths during RFA. After the RF treatment, a well-defined circular or oval ablation zone with white brown discoloration could be seen on the liver section of the ablation zone (Fig. 1). The mean long-axis diameters, as measured in the gross specimens of the four groups, were as follows: 12.3 ± 1.2 mm in group A, 25.6 ± 9.9 mm in group B, 25.4 ± 9.5 mm in group C and 21.4 ± 9.2 mm in group D (Table 2). The difference in long-axis diameters in group A and the other groups were statistically significant (p < 0.05). In addition, the mean short-axis diameters of the ablation zones in each group of rabbits are as follows: 11.1 ± 0.9 mm in group A; 20.7 ± 6.4 mm in group B; 17.4 ± 3.4 mm in group C; and 16.5 ± 6.7mm in group D (p < 0.05). The difference in short-axis diameters for group A and other groups were statistically significant (p < 0.05). Therefore, AHS pretreatment with RFA in the groups B, C, and D produced larger dimensions of coagulation than those of the group A (p < 0.05). However, regardless of the concentration of acetic acid in solutions, there were no significant differences in long- axis diameter and short-axis diameters of the coagulation necrosis among groups B, C, and D (p > 0.05).


Combined radiofrequency ablation and acetic acid hypertonic saline solution instillation: an in vivo study of rabbit liver.

Lee JM, Kim YK, Kim SW, Han JK, Kim SH, Choi BI - Korean J Radiol (2004 Jan-Mar)

Cut Sections of gross specimens in the four groups. In groups B, C, and D, the combined radiofrequency ablations with instillation of the acetic acid-hypertonic saline solutions produced greater ablation zones than that does radiofrequency alone (group A).A. Gross specimen of a group A (radiofrequency ablation only) rabbit shows a round pale-discolored area (arrow) in the liver.B. Gross specimen of a group B (radiofrequency ablation with 50% acetic acid instillation) rabbit shows an oval shaped discolored coagulation zone (arrows) and thrombosis (arrowheads) of small vessels within the zone.C. Gross specimen of a group C (radiofrequency ablation with 25% acetic acid instillation) rabbit shows greater area of the ablation zone (arrow) than those of groups A (A) and B (B).D. Gross specimen of a group D (radiofrequency ablation with 15% acetic acid instillation) rabbit shows a similar appearance with the ablation zone to group C. Note that the thrombosis of small vessels (arrowheads) are seen in the coagulation area (arrow).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2698111&req=5

Figure 1: Cut Sections of gross specimens in the four groups. In groups B, C, and D, the combined radiofrequency ablations with instillation of the acetic acid-hypertonic saline solutions produced greater ablation zones than that does radiofrequency alone (group A).A. Gross specimen of a group A (radiofrequency ablation only) rabbit shows a round pale-discolored area (arrow) in the liver.B. Gross specimen of a group B (radiofrequency ablation with 50% acetic acid instillation) rabbit shows an oval shaped discolored coagulation zone (arrows) and thrombosis (arrowheads) of small vessels within the zone.C. Gross specimen of a group C (radiofrequency ablation with 25% acetic acid instillation) rabbit shows greater area of the ablation zone (arrow) than those of groups A (A) and B (B).D. Gross specimen of a group D (radiofrequency ablation with 15% acetic acid instillation) rabbit shows a similar appearance with the ablation zone to group C. Note that the thrombosis of small vessels (arrowheads) are seen in the coagulation area (arrow).
Mentions: The RFA was technically successful in all test conditions. There were no deaths during RFA. After the RF treatment, a well-defined circular or oval ablation zone with white brown discoloration could be seen on the liver section of the ablation zone (Fig. 1). The mean long-axis diameters, as measured in the gross specimens of the four groups, were as follows: 12.3 ± 1.2 mm in group A, 25.6 ± 9.9 mm in group B, 25.4 ± 9.5 mm in group C and 21.4 ± 9.2 mm in group D (Table 2). The difference in long-axis diameters in group A and the other groups were statistically significant (p < 0.05). In addition, the mean short-axis diameters of the ablation zones in each group of rabbits are as follows: 11.1 ± 0.9 mm in group A; 20.7 ± 6.4 mm in group B; 17.4 ± 3.4 mm in group C; and 16.5 ± 6.7mm in group D (p < 0.05). The difference in short-axis diameters for group A and other groups were statistically significant (p < 0.05). Therefore, AHS pretreatment with RFA in the groups B, C, and D produced larger dimensions of coagulation than those of the group A (p < 0.05). However, regardless of the concentration of acetic acid in solutions, there were no significant differences in long- axis diameter and short-axis diameters of the coagulation necrosis among groups B, C, and D (p > 0.05).

Bottom Line: All procedures are technically successful.With instillation of 15% AHS solution, a marked decrease of tissue impedance (24.5+/-15.6 ohm ) and an increase of current (250 mA) occurred as compared to RFA alone.A low concentration of AHS (15%) showed similar effects in increasing the extent of RF-induced coagulation, but there were less side effects as compared to the high concentration of AHS.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, Seoul National University College of Medicine, Seoul, Korea. leejm@radcom.snu.ac.kr

ABSTRACT

Objective: We wanted to determine whether combined radiofrequency ablation (RFA) and acetic acid-hypertonic saline solution (AHS) instillation can increase the extent of thermally mediated coagulation in in vivo rabbit liver tissue. We also wished to determine the optimal concentration of the solution in order to maximize its effect on extent of the RFA-induced coagulation.

Materials and methods: Forty thermal ablation zones were produced in 40 rabbits by using a 17-gauge internally cooled electrode with a 1-cm active tip under ultrasound guidance. The rabbits were assigned to one of four groups: group A: RFA alone (n=10); group B: RFA with 50% AHS instillation (n=10); group C: RFA with 25% AHS instillation (n=10); group D: RFA with 15% AHS instillation (n=10). A range of acetic acid concentrations diluted in 36% NaCl to a total volume of 1 mL were instilled into the liver before RFA. The RF energy (30W) was applied for three minutes. After RFA, in each group, the maximum diameters of the thermal ablation zones in the gross specimens were compared. Technical success and the complications that arose were evaluated by CT and on the basis of autopsy findings.

Results: All procedures are technically successful. There were six procedure related complications (6/40; 15%): two localized perihepatic hematomas and four chemical peritonitis. The incidence of chemical peritonitis was highest for group B with the 50% AHS solution instillation (30%). With instillation of 15% AHS solution, a marked decrease of tissue impedance (24.5+/-15.6 ohm ) and an increase of current (250 mA) occurred as compared to RFA alone. With instillation of the solutions before RFA (group B, C and D), this produced a greater mean diameter of coagulation necrosis than the diameters for rabbits not instilled with the solution (group A) (p < 0.05). However, there was no significant difference between group B, C, and D.

Conclusion: Combined AHS instillation and RFA can increase the dimension of coagulation necrosis in the liver with a single application. A low concentration of AHS (15%) showed similar effects in increasing the extent of RF-induced coagulation, but there were less side effects as compared to the high concentration of AHS.

Show MeSH
Related in: MedlinePlus