[1] Univ Rome, Digest Endoscopy Unit, I-00128 Rome, Italy
[2] Univ Rome, Radiol Unit, I-00128 Rome, Italy
[3] Univ Rome, Fac Biomed Engn, I-00128 Rome, Italy
[4] Regina Apostolorum Hosp, Radiol Unit, Albano, Italy
[5] Univ Cattolica Sacro Cuore, Surg Endoscopy Unit, I-00168 Rome, Italy