J Korean Radiol Soc.  2003 Jun;48(6):447-458. 10.3348/jkrs.2003.48.6.447.

Transluminal Radio-Frequency Thermal Ablation Using a Stent-Type Electrode: an Experimental Study

• Kim YS
• Rhim H
• Song HY
• Shin JH
• Seo TS
• Kim TH
• Paik SS
• Kim Y
• Koh BH
• Cho OK
• Seo HS
• Cho BC
• Nam JH
• Kim SH
• Jin ED
• Kim JK
• Lee JH

• KMID: 1833708
• DOI: http://doi.org/10.3348/jkrs.2003.48.6.447

Abstract

PURPOSE
To assess the feasibility of transluminal radiofrequency thermal ablation using a stent-type electrode and to determine, by means of in-vitro and in-vivo animal studies, the appropriate parameters.
MATERIALS AND METHODS
In vitro: The radiofrequency electrode used was a self-expandable nitinol stent with 1cm insulated ends. A stent was placed in the portal vein of bovine liver, and ablations at target temperatures of 70, 80, 90, and 100degrees C were performed. Ablated sizes were measured longitudinally. In vivo: Four mongrel dogs were anesthetized, and a stent was inserted in the common bile duct under fluoroscopic guidance through an ultrasound-guided gall bladder puncture site. The ablation temperature was set at 80 degrees C, and each dog underwent proximal and distal esophageal ablations lasting 12 minutes. They were sacrificed immediately.
RESULTS
In-vitro: Ablated sizes showed significant correlation with target temperatures (r>0.04; p<0.05). Although most lesions were fusiform, dumbbell-shaped lesions with central thinning were found in two cases in the 70degrees C group. In all cases in the 70 degrees C and 80 degrees C group, the length of the insulated segment was less than 1 cm. In-vivo: At microscopy, tissues at the center of the biliary stent showed more prominent pathological change than those at the periphery while those remote from the stent showed minimal or no change. In esophageal ablations, the mean highest temperature was 48.6 degrees C. Microscopy demonstrated the destruction and shedding of mucosa, edema, and coagulation necrosis of submucosa, but in muscle layers no abnormalities were apparent.
CONCLUSION
Transluminal radio-frequency thermal ablation using a stent-type electrode may be useful for elongating patency. The appropriate target temperature for biliary ablation is 80 degrees C.

Keyword

Interventional procedures, experimental studies; Radiofrequency (RF) ablation; Esophagus, interventional procedures; Bile ducts, interventional procedures

MeSH Terms

Animals
Common Bile Duct
Dogs
Edema
Electrodes*
Liver
Microscopy
Mucous Membrane
Necrosis
Portal Vein
Punctures
Stents
Urinary Bladder