1. Department of GastroenterologyShandong Provincial Hospital affiliated to Shandong University Jinan 250021 P. R. China
2. Department of GastroenterologyShandong Provincial Hospital affiliated to Shandong First Medical University Jinan 250021 P. R. China
3. Shandong Provincial Engineering and Technological Research Center for Liver Diseases Prevention and Control Jinan 250021 P. R. China