The various imaging aspects of chronic pancreatitis.

The first aspect of chronic pancreatitis (CP) is the early phase of relapsing pancreatitis (RP) in which episodes of mild acute pancreatitis (MAP) or severe acute pancreatitis (SAP) occur repeatedly over a period of time [1, 2]. In RP modifications occur mainly at the ductal structures. These can be functional (altered response to secretin administration, late discharge of pancreatic juices into the duodenum) and/or morphological (ectasia of the branch ducts, irregularity of the main duct walls), or so minute that imaging cannot depict them. The morphology, the dimensions and the structure of the pancreatic gland are normal at ultrasonography (US), computed tomography (CT: Figure 1a) and magnetic resonance (MR). The ductal structures may be normal (Figure 1a) or dilated in relation to the size of the obstruction. In this phase, the diagnostic contribution of imaging lies in identifying a series of pathologies which are all rather different, but are all responsible for impairing the flow of pancreatic and/or biliary juice into the duodenum: at the biliary tract, imaging can demonstrate microlithiasis of the common bile duct and/or papilla [3, 4, 5, 6], postinflammatory papillary stenosis, dysfunction of the sphincter of Oddi [4, 6], ampullary tumors and congenital anomalies [7, 8, 9]; at the pancreatic ductal system imaging can reveal tumors, congenital anomalies [4, 10, 11, 12, 13, 14] and SAP effects [15] and, finally, at the duodenum, imaging can identify tumors, congenital anomalies and duodenal dystrophy.