Non-invasive imaging in pancreatitis

Ultrasound is indicated in the first 24 hours, mainly to identify gallstones as the cause of pancreatitis rather than to contribute to the diagnosis

Early endoscopic retrograde cholangiopancreatography (ERCP) should be considered in patients with gallstone induced acute pancreatitis if cholangitis and biliary obstruction are suspected

To stage, and identify complications in, patients with persisting organ failure, signs of sepsis, or deterioration in clinical status 3-7 days after admission, a contrast enhanced computed tomography (CE-CT) scan should be considered

Early CE-CT (<72 hours after presentation) may underestimate the extent of necrosis as there is often a lag effect between disease extent and radiological appearances, therefore giving false assurance and less reliable surgical information on the extent of pancreatic necrosis

Despite the high spatial resolution of CE-CT, detection of gallstones within the common bile duct can be limited by their isodensity to the bile fluid; however, sensitivity to stones is very good and similar to that of magnetic resonance imaging

ERCP and endoscopic ultrasound are yet more sensitive but are invasive

CE-CT remains the preferred imaging modality for severe pancreatitis; its ready availability and use in subsequent interventional procedures, with excellent depiction of any complications, makes it the front runner

Magnetic resonance imaging has a growing evidence base, but it is not used widely yet