Korean J Radiol.  2002 Dec;3(4):245-253. 10.3348/kjr.2002.3.4.245.

Saline-Enhanced Radiofrequency Thermal Ablation of the Lung: A Feasibility Study in Rabbits

• Lee JM
• Kim SW
• Li CA
• Youk JH
• Kim YK
• Jin Z
• Chung MJ
• Lee MS

• KMID: 1118792
• DOI: http://doi.org/10.3348/kjr.2002.3.4.245

Abstract

OBJECTIVE
To assess the feasibility and safety of CT-guided percutaneous transthoracic radiofrequency ablation (RFA) with saline infusion of pulmonary tissue in rabbits. MATERIALS AND METHODS: Twenty-eight New Zealand White rabbits were divided into two groups: an RFA group (n=10) and a saline-enhanced RFA (SRFA) group (n=18). In the RFA group, percutaneous RFA of the lung was performed under CT guidance and using a 17-gauge internally cooled electrode. In the SRFA group, 1.5 ml of 0.9% saline was infused slowly through a 21-gauge, polyteflon-coated Chiba needle prior to and during RFA. Lesion size and the healing process were studied in rabbits sacrificed at times from the day following treatment to three weeks after, and any complications were noted. RESULTS: In the SRFA group, the mean diameter (12.5+/-1.6 mm) of acute RF lesions was greater than that of RFA lesions (8.5+/-1.4 mm) (p < .05). The complications arising in 12 cases were pneumothorax (n=8), thermal injury to the chest wall (n=2), hemothorax (n=1), and lung abscess (n=1). Although procedure-related complications tended to occur more frequently in the SRFA group (55.6%) than in the RFA group (20%), the difference was not statistically significant (p = .11). CONCLUSION: Saline-enhanced RFA of pulmonary tissue in rabbits produces more extensive coagulation necrosis than conventional RFA procedures, without adding substantial risk of serious complications.

Keyword

Lung CT, interventional procedures; Radiofrequency, tissue ablation; Animal experiment

MeSH Terms

Animal
*Catheter Ablation
Lung/radiography/*surgery
Lung Neoplasms/radiography/*surgery
Male
Rabbits
Sodium Chloride
Tomography, X-Ray Computed

Figure

• 

  Fig. 1 Radiofrequency ablation in a rabbit in the radiofrequency group. A. Computed tomographic section obtained during radiofrequcy ablation. The right lower lobe is penetrated posteriorly by an electrode along which an ovoid opacity extends (arrows). B. Contrast-enhanced CT scan obtained after the procedure depicts nonenhancing opacity (arrows) in the central portion of the right lobe. Note good enhancement of the pulmonary vessels in the area of ablation. C. Gross specimen demonstrates an 8-mm central zone of coagulation necrosis surrounded by a dark-brown, 1-mm-thick hemorrhagic rim. D. Microscopic image of the central ablation zone (A) shows that this contains pyknotic nuclei and eosinophilic cytoplasm, and that hemorrhagic congestion (arrows) has occurred at the border between the ablation area and normal pulmonary parenchyma (P).

• 

  Fig. 2 Saline-enhanced radiofrequency ablation in a rabbit in the saline-enhanced radiofrequency group. A. A 17-gauge RF electrode and a 21-gauge coated Chiba needle have been placed in the right lower lobe of the lung. To maximize the effect of saline infusion, the tip of the needle is positioned 3mm posterior to the tip of the electrode. B. Axial CT scan obtained after RF application shows a rounded opacity 12 mm in diameter (arrows), corresponding to coagulated alveoli and pneumothorax. C. Gross specimen demonstrates a dark-brown area of coagulative necrosis surrounded by a peripheral hemorrhagic rim. Note the somewhat lobulated margin of the ablation zone, with focal sparing of the pulmonary artery (arrow).

• 

  Fig. 3 Follow-up CT scans of a rabbit in the subacute subgroup obtained through a radiofrequency-ablated lesion both immediately and two weeks after treatment. A. CT scan obtained immediately after the procedure depicts a large opacity involving the right lower lobe of the lung (arrows). B. Follow-up CT scan obtained two weeks after the procedure shows markedly decreased right lung volume, as well as hazy opacity induced by RFA (arrows). C. Microscopic image (×1) demonstrates marked fibrotic change involving both the segmental bronchi (arrowheads) of the right lower lobe and the ablated lesion (arrows). D. Microscopic image (×40) reveals central coagulation necrosis (C) and formation of a thick peripheral fibrous capsule (F).

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