5.1　Introduction

The diagnosis of chronic pancreatitis（CP）is based on a combination of clinical，laboratory and imaging findings（Majumder and Chari 2016）.Ideally，the most definitive diagnostic criteria for CP should be histologic evidence，but obtaining it on a routine basis is rarely available（Forsmark 2000，2013）.In the clinical practice，ERCP has been generally suggested as the gold standard because of its high sensitivity（70-94%）and specificity（80-100%）of detecting structural abnormalities（Forsmark 2000；Forsmark and Toskes 1995；Etemad and Whitcomb 2001；Adler et al.2006；Feldman et al.2015；Shamamian et al.2009；Nagar and Gorelick 2005）although it is unable to visualize any changes within the parenchyma of the gland and only allows the visualization of the pancreatic ductal system.(https://www.daowen.com)