Rad-8. Imaging evolution of lung tumors and the complications encountered after percutaneous CT guided radiofrequency ablation.

Three-year data from the IRB-approved study "Radiofrequency Ablation (RFA) of Primary and Secondary Lung Malignancies" was reviewed with regard to treated tumor evolution and complications encountered. Patients entered into this study had primary or secondary pulmonary tumors as identified on diagnostic CT. Patients who could benefit from pulmonary sparing surgery were offered this procedure. Candidates included those patients with primary lung tumors and co-morbidity preventing traditional surgical resection, as well as limited secondary pulmonary tumor burden. To date, 164 patients have been treated. Thirty-nine of the patients had primary pulmonary tumors with the remaining patients having metastatic disease. RFA intra-operative imaging uniformly demonstrated gas and heat expansion of the targeted tumor. A peri-ablation zone of parenchymal density appeared at approximately 60 minutes and was of maximal density at approximately 12 hours post RFA. These changes resolved over the next few weeks with the treated tumor diameter returning to the pre RFA diameter at approximately 3-6 months. Complications encountered included one pulmonary abscess, two episodes of parenchymal hemorrhage, three COPD exacerbations, and five grounding pad skin burns. Complications listed are somewhat preventable (burns). Pictorial display demonstrates the varied evolution of a lung tumor treated with RFA. Most tumors continued to condense over time, however some would remain a static size with a heterogeneous appearance composed of pockets of gas with nonenhancing tissue.

Patrick E. Sewell, Jr, MD. University of Mississippi Medical School, Department of Radiology, Division of Minimally Invasive Surgery, Jackson MS.