Acute pancreatitis is a common disease characterized by nonspecific pancreatic inflammation associated with a variety of different etiologic factors, including alcohol abuse and gallstone disease. Release of proteolytic enzymes in acute pancreatitis may produce inflammation of peripancreatic fat with thickening of retroperitoneal fascial planes. There are two distinct types of pancreatitis: Acute Edematous Pancreatitis and Acute Hemorrhagic Pancreatitis. During acute edematous pancreatitis, the pancreas is grossly enlarged and pale, and there is considerable interstitial edema and mild inflammatory exudates.
Acute edematous pancreatitis usually subsides without sequelae, but in rare cases may progress to a more severe and protracted form. Acute Hemorragic pancreatitis is characterized by destruction of the pancreatic parenchyma, necrosis of small blood vessels, interstitial hemorrage, fat necrosis, and a marked pancreatic and peripancreatic inflammatory reaction. In this kind of disease, if the patient survives, the pancreas usually shows considerable fibrosis and calcification with destruction of both islet cells tissue and acinar and ductular cells. A CT examination allows to characterize these two forms of pancreatitis and evaluate the degree of inflammatory edema of peripancreatic tissue. In the acute hemorrhagic pancreatitis CT shows a grossly enlargement of the gland where we can see different areas with low attenuation values; after i.v. administration of contrast media the contrast enhancement of the gland is quite irregular due to presence of different areas of normal perfusion (vital parenchyma) and abnormal/decreased perfusion (edema, necrosis). Paralitic ileus is almost associated to this disease.