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Radiofrequency ablation of the gastrointestinal tract with a stent-like electrode: experimental study.

Byun JN, Kang SG, Choi JY, Kim DH, Lee JM, Kim YC, Ki KH, Lee CG - Korean J Radiol (2003 Jan-Mar)

Bottom Line: To determine the gross and microscopic findings, six animals were sacrificed immediately after the procedure and the results obtained under the different sets of conditions were correlated.The gross and histologic changes occurring showed close correlation under all six sets of conditions.Use of the stent-like electrode proves technically feasible but to determine the nature of the chronic change occurring in the gastrointestinal tract after RF ablation, further investigation and long-term follow-up in animals are required.

View Article: PubMed Central - PubMed

Affiliation: Department of Diagnostic Radiology, Chosun University College of Medicine, Gwangju, Korea.

ABSTRACT

Objective: To assess the technical feasibility of a newly designed stent-like electrode in rabbits.

Materials and methods: A stent-like electrode was knitted from a single thread of nitinol wire and interconnected to a generator using similar wire. In order to gauge the extent of radiofrequency ablation (RFA), we measured the depth of the ablated area in cow liver using a combination of 180-sec time intervals and 20-watt power increments. For data processing, Cox regression analysis was used. RFA was also applied to the small intestine of rabbits using this stent-like electrode under six different sets of conditions: 10 watts for 1 min, 10 watts for 2 mins, 20 watts for 1 min, 20 watts for 2 mins, 30 watts for 1 min, and 30 watts for 2 mins. To determine the gross and microscopic findings, six animals were sacrificed immediately after the procedure and the results obtained under the different sets of conditions were correlated. Eight rabbits were monitored for 4 weeks prior to sacrifice.

Results: For both ex-vivo and in-vivo ablations, the depth of the thermal lesion showed linear correlation with both the duration of RFA and the power applied. RFA of the duodenum was technically successful in all 14 rabbits. The acute changes occurring in the rabbits' small intestine included color change, cytoplasmic denaturation, fibrin deposition and hemorrhage, among which hemorrhage of the mucosal layer was the earliest finding. RF ablation for 2 mins at 30 watts caused serosal hemorrhage. The gross and histologic changes occurring showed close correlation under all six sets of conditions.

Conclusion: Use of the stent-like electrode proves technically feasible but to determine the nature of the chronic change occurring in the gastrointestinal tract after RF ablation, further investigation and long-term follow-up in animals are required.

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Related in: MedlinePlus

Graph of power applied vs. depth of ablation, showing linear correlation between these two parameters.
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Figure 6: Graph of power applied vs. depth of ablation, showing linear correlation between these two parameters.

Mentions: A total of 40 ablations were performed in the excised livers, showing that the dimensions of the thermal lesions increased both with elapsed time and increased RF energy levels. Cox regression analysis demonstrated that the thickness of the resultant lesion showed linear correlation with both elapsed time (Fig. 5) and the power applied (Fig. 6). The regression equation used was as follows: diameter of the thermal lesion= -11.436+1.57 elapsed×time+0.315×watts (p value < .001; r2 , 82%).


Radiofrequency ablation of the gastrointestinal tract with a stent-like electrode: experimental study.

Byun JN, Kang SG, Choi JY, Kim DH, Lee JM, Kim YC, Ki KH, Lee CG - Korean J Radiol (2003 Jan-Mar)

Graph of power applied vs. depth of ablation, showing linear correlation between these two parameters.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2698054&req=5

Figure 6: Graph of power applied vs. depth of ablation, showing linear correlation between these two parameters.
Mentions: A total of 40 ablations were performed in the excised livers, showing that the dimensions of the thermal lesions increased both with elapsed time and increased RF energy levels. Cox regression analysis demonstrated that the thickness of the resultant lesion showed linear correlation with both elapsed time (Fig. 5) and the power applied (Fig. 6). The regression equation used was as follows: diameter of the thermal lesion= -11.436+1.57 elapsed×time+0.315×watts (p value < .001; r2 , 82%).

Bottom Line: To determine the gross and microscopic findings, six animals were sacrificed immediately after the procedure and the results obtained under the different sets of conditions were correlated.The gross and histologic changes occurring showed close correlation under all six sets of conditions.Use of the stent-like electrode proves technically feasible but to determine the nature of the chronic change occurring in the gastrointestinal tract after RF ablation, further investigation and long-term follow-up in animals are required.

View Article: PubMed Central - PubMed

Affiliation: Department of Diagnostic Radiology, Chosun University College of Medicine, Gwangju, Korea.

ABSTRACT

Objective: To assess the technical feasibility of a newly designed stent-like electrode in rabbits.

Materials and methods: A stent-like electrode was knitted from a single thread of nitinol wire and interconnected to a generator using similar wire. In order to gauge the extent of radiofrequency ablation (RFA), we measured the depth of the ablated area in cow liver using a combination of 180-sec time intervals and 20-watt power increments. For data processing, Cox regression analysis was used. RFA was also applied to the small intestine of rabbits using this stent-like electrode under six different sets of conditions: 10 watts for 1 min, 10 watts for 2 mins, 20 watts for 1 min, 20 watts for 2 mins, 30 watts for 1 min, and 30 watts for 2 mins. To determine the gross and microscopic findings, six animals were sacrificed immediately after the procedure and the results obtained under the different sets of conditions were correlated. Eight rabbits were monitored for 4 weeks prior to sacrifice.

Results: For both ex-vivo and in-vivo ablations, the depth of the thermal lesion showed linear correlation with both the duration of RFA and the power applied. RFA of the duodenum was technically successful in all 14 rabbits. The acute changes occurring in the rabbits' small intestine included color change, cytoplasmic denaturation, fibrin deposition and hemorrhage, among which hemorrhage of the mucosal layer was the earliest finding. RF ablation for 2 mins at 30 watts caused serosal hemorrhage. The gross and histologic changes occurring showed close correlation under all six sets of conditions.

Conclusion: Use of the stent-like electrode proves technically feasible but to determine the nature of the chronic change occurring in the gastrointestinal tract after RF ablation, further investigation and long-term follow-up in animals are required.

Show MeSH
Related in: MedlinePlus