Reportage in the interventional neuroradiology service in Pasteur 2 Hospital, Nice, France. Treating a cerebral aneurysm through embolization. This endovascular treatment consists of introducing a catheter into the brain and filling the aneurysm with platinum coils in order to clot it and prevent it splitting. The embolization is carried out under fluoroscopic guidance. Preparing a hyper-compliant balloon. This balloon is very soft and will adapt to the artery and help embolization. It is filled with diluted contrast agent.