Aims In this article we present our experience with radiofrequency ablation (RFA) in the treatment of 105 renal tumors. Materials and Methods RFA was performed on 105 renal tumors in 97 patients, with a mean tumor size of 32 mm (11-68 mm). The mean patient age was 71.7 years (range, 36-89 years). The ablations were carried out under ultrasound (n = 43) or CT (n = 62) guidance. Imaging followup was by contrast-enhanced CT within 10 days and then at 6-monthly intervals. Multivariate analysis was performed to determine variables associated with procedural outcome. Results Eighty-three tumors were completely treated at a single sitting (79%). Twelve of the remaining tumors were successfully re-treated and a clinical decision was made not to re-treat seven patients. A patient with a small residual crescent of tumor is under follow-up and may require further treatment. In another patient, re-treatment was abandoned due to complicating pneumothorax and difficult access. One patient is awaiting further re-treatment. The overall technical success rate was 90.5%. Multivariate analysis revealed tumor size to be the only significant variable affecting procedural outcome. (p = 0.007, Pearson v 2 ) Five patients had complications. There have been no local recurrences. Conclusion Our experience to date suggests that RFA is a safe and effective, minimally invasive treatment for small renal tumors.Keywords Kidney Á Computed tomography Á Kidney neoplasms Á Therapeutic radiology Á Radiofrequency ablation In recent years radiofrequency ablation (RFA) has continued to evolve into an effective image-guided tool for the minimally invasive destruction of small-volume, discrete tumors. While the vast majority of experience has been gained in the treatment of hepatocellular carcinoma (HCC) and colorectal metastases in the liver, recent attention has turned to renal tumors [1][2][3][4]. Renal tumors represent 3% of all human tumors [5] and the 5-year survival rate for RCC has increased from 34% in 1954 to 62% in 1996 [6]. There has also been a 126% increase in the incidence of renal cell carcinoma in the United States since 1950 [6]. Both the increased incidence and the improved survival are largely attributable to the radiologic detection of early-stage disease [7]. In addition, despite other strategies, this detection is largely serendipitous at cross-sectional imaging studies for other symptomatology. Some series have suggested that up to 85% of all renal tumors are in fact detected incidentally [8]. The improved outcome from smaller-volume tumors has been reflected by the TNM classification

Early experience suggests that radiofrequency ablation is a safe, well-tolerated, and minimally invasive therapy for patients with solid renal masses. In the era of nephron-sparing surgery, radiofrequency ablation may have a role in the management of small problematic renal masses.

In vitro, i.v. contrast-enhanced MDCT is more sensitive than first-order aortic branch-selective DSA in detecting active hemorrhage unless the catheter position is highly superselective and is close to the bleeding artery. These results suggest that MDCT can be used as the initial imaging technique in the diagnosis of active hemorrhage if the clinical condition of the patient allows.

Better assessment of stone size, and therefore higher accuracy of diagnosis, could be achieved if attention is paid to more subtle but nonetheless important signs. These include compressed air in dependent areas of the duodenal lumen, an area of soft-tissue rather than fluid density surrounding the calcified rim of the stone, and a faint radiolucency in or beyond this soft-tissue area that could represent laminations of fat or air in the stone.