Imaging evaluation of post-pancreatitis infection

Acute pancreatitis affects around 40 per 100.000 of the general population and 20-30% of attacks are severe. Mortality is usually associated to septic multiorgan dysfunction syndrome caused by secondary infection of pancreatic or peripancreatic necrosis. The diagnosis of acute pancreatitis is generally based on clinical and laboratory findings. However CT is the imaging technique of choice for detecting complications. Patients with complicated pancreatitis require multiple follow-up examinations. Substitution of US or MRI for CT in certain cases would reduce the radiation dose considerably. Complicated pseudocysts and other pancreatic collections may contain solid debris, which is best depicted by MRI. Abscesses are suggested when gas is present in a pancreatic or peripancreatic collection. MRI can reveal air-fluid levels or large pockets of gas, but CT is more sensitive for small gas collections. US or CT-guided percutaneous drainage of pancreatic abscesses or infected collections is a useful therapeutic approach in acute cases obviating the need for unnecessary surgery. On the other hand infected necrosis can not be successfully treated percutaneously due to its thicker consistency. In this review, the role of different imaging modalities in the evaluation of post-pancreatitis infection as well as in the treatment planning will be discussed.