Michele Scialpi1, Irene Piscioli2, Alfredo D'Andrea3. 1. Department of Surgical, Radiological and Odontostomatological Sciences, Division of Radiology 2, Perugia University, S. Maria della Misericordia Hospital, S. Andrea delle Fratte, Perugia, Italy. Electronic address: michelescialpi@libero.it. 2. Division of Radiology, Budrio Hospital, ASL Bologna, Budrio, Italy. 3. Division of Radiology, San Giuseppe Moscati Hospital, Aversa, Caserta, Italy.