1. Department of Radiology, University Hospital of Catania, 95100 Catania, Italy
2. Department of Neurosurgery, University Hospital of Catania, 95100 Catania, Italy
3. Department of Otorhinolaryngology, University Hospital of Catania, 95100 Catania, Italy
4. Department of Neuroradiology, University Hospital of Catania, 95100 Catania, Italy