Imaging of Acute and Chronic Pancreatitis

Abstract

Acute pancreatitis (AP) is an acute inflammatory process of the pancreas that frequently involves peripancreatic tissues and even remote organ systems. The severity of the disease varies widely, from mild forms only affecting the pancreas to severe disease with multisystemic organ failure and death. The major pathobiological processes underlying AP are inflammation, edema, and necrosis of pancreatic tissue as well as inflammation and injury of extrapancreatic organs. Far more patients have interstitial pancreatitis than necrotizing pancreatitis (approximately 85% vs. 15%). Organ failure occurs more commonly in patients with necrotizing pancreatitis than in those with interstitial pancreatitis (approximately 50% vs. 5–10%). Mortality is higher in patients with necrotizing pancreatitis than in those with interstitial pancreatitis, in which there is little necrosis (approximately 17% vs. 3%). The prevalence of infected necrosis in patients with necrotizing pancreatitis is 15–20% and among this subgroup of patients mortality is greater than in those with sterile necrosis (approximately 30% vs. 12%). Although alcohol abuse and gallstone disease account for 70–80% of the cases of acute pancreatitis, the exact mechanisms by which these factors initiate the pathologic process are presently unknown.