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[en] Renal cell cancer is the most frequent malignant tumor of the kidney. Depending on tumor size, extension and general condition, radical or partial nephrectomy, which meanwhile can be performed laparoscopically, is still the therapy of choice. Patients with an increased surgical risk, or suffering from additional renal tumors or tumor in a single kidney, percutaneous tumor ablation is a helpful therapeutical option. Among all thermal ablation procedures, most experiences exist with radiofrequency ablation (RFA). A significant advantage of this technique is the possibility of direct puncture of the tumor without Seldinger technique and track ablation. This helps to reduce the risk of bleeding and tumor seeding within the puncture track. By use of modern ablation probes, lesions of up to 5 cm diameter can be created without repositioning of the probe. Initial superselective particle embolization is recommended in tumors beyond 3 cm in size, because renal cell cancer is often hypervascularized and devasularization helps to reduce ablation time. Furthermore, the tumor location within the kidney is influencing the ablation result. Exophytically growing lesions or tumors within the renal parenchyma can be treated with a safety margin. Tumors in a central location or with broad contact to the collecting system are no candidates for thermal ablation, because of an increased risk of thermal collateral damage. Computed tomography is an optimal imaging modality and crucial to planning, performing and controlling of a successful percutaneous RFA. Based on the previous experiences of 300 published cases, renal RFA results in an over 90% success rate associated with a low complication rate. A randomized controlled study comparing RFA and surgery is necessary to answer the question whether RFA can be considered therapy of first choice even for patients, who are according to the actual evidence surgical candidates. (orig.)

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[en] Purpose: To evaluate the effectiveness of a percutaneous radiofrequency ablation device, consisting of a LeVeen probe and a newly developed 200-W radiofrequency generator. Material and Method: In 20 patients (9 male, 11 female), 30 primary and secondary lever malignancies were treated by CT-guided percutaneous radiofrequency ablation. The patients were separated in a potentially curable (n=10) and a palliative (n=10) treatment group. The treatment was performed using an umbrella-shaped LeVeen probe with a diameter of 3.5 cm or 4 cm and a 200-W generator (Radiotherapeutics, Mountain View, CA, USA). All interventions were performed under general anesthesia by a standardized treatment protocol. The size of the lesions treated ranged from 2.2x2x2 cm to 10.8x10.1x10.5 cm. Results: In all patients, the correct placement of the probe and radiofrequency ablation was technically successful. In two patients more than one treatment session was necessary to achieve the intended treatment result. In all patients of the potentially curable group a complete tumor necrosis could be achieved, whereas in the palliative treatment group complete tumor necrosis was only achievable in one patient. The achieved necrosis size ranged from 2.4x2.8x2.5 cm to 9.2x8x10.5 cm. In one patient a colon fistula was observed 4 weeks after treatment. No further complications were observed. The follow-up period ranges from 1 to 15 months (mean 4.5 months). Conclusion: By use of a powerful generator in combination with a LeVeen probe percutaneous treatment of even large liver tumors is possible. Radiofrequency ablation is a safe procedure for the minimal-invasive therapy of non resectable liver neoplasms. (orig.)

[en] Over the last few years, cross-sectional imaging became clinically accepted for qualitative and quantitative analysis of left ventricular (LV) function. The results have an impact on diagnosis, therapy and follow-up, and some parameters even proved to be independent predictors of mortality. Besides well established cardiologic techniques, such as ventriculography and echocardiography, more recent radiologic techniques, especially magnetic resonance imaging (MRI) and multislice spiral computed tomography (MSCT), became accepted for imaging of LV function. Assessment of LV function with cardiac MRI is based on cine sequences. Over the last years, parallel imaging techniques, fast imaging with steady state free precession and real time sequences were successfully introduced. Further improvements were achieved by stress examinations and MR-tagging. Cardiac MSCT with retrospective ECG-dating allows for reliable determination of LV volumes. Assessment of wall motion is feasible but limited to some degree. Nevertheless, cardiac MSCT is a powerful alternative for patients with contraindications to MRI. Aim of this article is to review theoretical and technical aspects, opportunities and limitations of MRI and MSCT for functional imaging of the heart. (orig.)