1. Gastroenterology Unit, Department of Biomedical and Clinical Sciences, “L. Sacco” Hospital, University of Milan, Milan, Italy;
2. Radiology Unit, Fatebenefratelli “L. Sacco” University Hospital, Milan, Italy;
3. Clinical Epidemiology and Biometeric Unit, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy;
4. Gastroenterology, Hepatology, and Digestive Endoscopy Section, Department of Medicine and Surgery, University of Perugia, Perugia, Italy;
5. Gastroenterology Unit, Santa Maria Della Misericordia Hospital, Perugia, Italy.