Efficacy and Safety of IRE for RMs

Background: Electroporation or electropermeabilisation is a novel technique with the potential to overcome the main disadvantages of thermal ablation. It utilizes electric pulses, traveling between two or more electrodes, to create 'nanopores' in the cell membrane. If the applied current reaches a certain threshold these 'nanopores' become permanent resulting in cell death. The use of electric current means that IRE is not susceptible to 'thermal sink' leading to consistent ablation results. IRE ablation targets the cell membrane, sparing tissue architecture and minimizing damage to blood vessels, nerves and the renal collecting system. The first in human studies have proven the safety of IRE for the ablation of small renal masses. However the efficacy of IRE through histopathological examination of an ablated renal tumour has not yet been studied, compromising the correct and scientific evaluation of this new technology. Primary Objectives: * To determine the efficacy of IRE ablation of renal masses , measured by histopathologic examination of the targeted tumour. * To determine the safety of IRE ablation of renal masses, by evaluating device and procedural adverse events. Secondary Objectives: * To evaluate the efficacy of MRI in the imaging of ablation success, extend of the ablation zone, one and four weeks post IRE ablation. * To evaluate the efficacy of CEUS in the imaging of ablation success, extend of the ablation zone, one and four weeks post IRE ablation. Population: 10 patients, age ≥ 18 years, presenting with a solid enhancing mass, who are candidates for radical nephrectomy. Intervention: Eligible patients will receive IRE ablation of their renal mass 4 weeks prior to radical nephrectomy. Follow-up at one and four weeks post IRE will be performed using MRI and CEUS imaging. After radical nephrectomy histopathological examination will be performed to evaluate IRE ablation success.