N Morelli1, M Spallazzi2, E Rota3, E Michieletti4. 1. Neurology and Radiology UnitGuglielmo da Saliceto HospitalPiacenza, Italy. 2. Department of Medicine and Surgery, Section of NeurologyAzienda Ospedaliero-UniversitariaParma, Italy. 3. Neurology UnitSan Giacomo HospitalNovi Ligure, Alessandria, Italy. 4. Radiology UnitGuglielmo da Saliceto HospitalPiacenza, Italy.