1. Department of Medical Imaging, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710004, P.R. China
2. Department of Ophthalmology, The First Hospital of Xi'an, Xi'an, Shaanxi 710002, P.R. China
3. Department of Gastroenterology, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710004, P.R. China