J Korean Radiol Soc.  2004 May;50(5):343-351. 10.3348/jkrs.2004.50.5.343.

Percutaneous Radiofrequency Thermal Ablation of Lung VX2 Tumors in a Rabbit Model: Evaluation with Helical CT Findings for the Complete and Partal Ablation

• Jin GY
• Han YM
• Lim YS
• Jang KY
• Lee SY
• Chung GH

• KMID: 1593964
• DOI: http://doi.org/10.3348/jkrs.2004.50.5.343

Abstract

PURPOSE
To evaluate the radiologic findings for complete and partial ablation after percutaneous CT-guided transthoracic radiofrequency ablation (RFA) of lung VX2 tumor implanted in rabbits.
MATERIALS AND METHODS
Thirteen rabbits with successfully implanted lung VX2 were used. Three rabbits as controls did not receive RFA while the other ten rabbits underwent RFA; 5 complete and 5 partial. RFA was performed using an internally cooled, 17-gauge electrode (Radionics, Burlington, MA) with a 1-cm active tip under CT guidance. Postprocedural CT was performed within 3 days, and we analyzed the ablated size, enhancement pattern, shape, margin, and complications of the complete and partial ablation groups. Rabbits were sacrificed after postprocedural CT with an overdose of ketamine, and pathologic findings of the ablated groups were compared with those of the control group.
RESULTS
The size of the ablated lesions and the enhancement pattern differed between the completely and partially ablated groups on chest CT. The size of the ablated lesions was increased by 47.1% in the completely ablated group and by 2.1% in the partially ablated group. In the completely ablated group, VX2 tumor showed absolutely no enhancement, whereas only ablated pulmonary parenchyma outside VX2 showed mild enhancement on enhanced CT. In the partial ablated group, a part of VX2 became strongly enhanced on enhanced CT. On microscopic examination, the completely ablated group demonstrated that a viable tumor cell was not visible. In the partially ablated group, however, a viable tumor cell within the surrounding fibrous capsule on the peripheral area of the VX2 was observed.
CONCLUSION
The important CT findings for evaluation of complete and partial RFA are the ablated size and enhancement pattern of the ablated lesion.

Keyword

Computed tomography (CT); Interventional procedures; Lung neoplasms, therapy; Radiofrequency ablation; Animals

MeSH Terms

Animals
Catheter Ablation
Electrodes
Ketamine
Lung*
Rabbits
Tomography, Spiral Computed*
Tomography, X-Ray Computed
Ketamine