Imaging of acute pancreatitis and its complications. Part 1: acute pancreatitis.

Acute pancreatitis is an acute inflammatory disease of the pancreas that may also involve surrounding tissues or remote organs. The Atlanta classification of acute pancreatitis was introduced in 1992 and divides patients into mild and severe groups based on clinical and biochemical criteria. Recently, the terminology and classification scheme proposed at the initial Atlanta Symposium have been reviewed and a new consensus statement has been proposed by the Acute Pancreatitis Classification Working Group. Generally, imaging is recommended to confirm the clinical diagnosis, investigate the etiology, and grade the extend and severity of the acute pancreatitis. Ultrasound is the first-line imaging modality in most centers for the confirmation of the diagnosis of acute pancreatitis and the ruling out of other causes of acute abdomen, but it has limitations in the acute clinical setting. Computed tomography not only establishes the diagnosis of acute pancreatitis, but also enables to stage severity of the disease. Magnetic resonance imaging has earned an ever more important role in the diagnosis of acute pancreatitis. It is especially useful for imaging of patients with iodine allergies, characterizing collections and assessment of an abnormal or disconnected pancreatic duct. The purpose of this review article is to present an overview of the acute pancreatitis, clarify confusing terminology, underline the role of ultrasound, computed tomography and magnetic resonance imaging according to the proper clinical context and compare the advantages and limitations of each modality.