1. Gastroenterology Unit, Hospital of Imola, University of Bologna, Imola, Italy
2. Gastroenterology and Endoscopy Unit, Arcispedale Santa Maria Nuova di Reggio Emilia, Reggio Emilia, Italy
3. Department of Medical and Surgical Sciences, University of Bologna, Bologna, Italy
4. Endoscopy Unit, Centre Chirurgical Lyon Mermoz, Lyon, France