1. Institute of Radiology, Second University of Naples, 80138 Naples, Italy
2. Department of Radiology, Cardarelli Hospital, 80123 Naples, Italy
3. Department of Radiology, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA
4. Department of Radiology, Duke University Medical Center, Durham, NC 27710, USA
5. Department of Medical, Surgical and Neuro Sciences, Diagnostic Imaging, University of Siena, Azienda Ospedaliera Universitaria Senese, Viale Bracci 10, 53100 Siena, Italy