In suspected acute pancreatitis, which test is typically performed to evaluate gallstone etiology?

• A. CT scan
• B. MRCP
• C. Abdominal ultrasound
• D. Barium swallow

Answer: (C)

When pancreatitis might be caused by gallstones, the imaging test of choice is abdominal ultrasound because it directly visualizes gallstones and assesses the biliary tract. It’s noninvasive, quick, inexpensive, and widely available, and it can show gallstones, sludge, gallbladder wall changes, and dilation of the common bile duct suggesting obstruction. If gallstones or biliary obstruction are found, that guides management, such as pursuing interventions for ductal stones if needed.

CT scans are excellent for evaluating pancreatic tissue and complications but are less sensitive for detecting gallstones themselves. MRCP provides a detailed view of the biliary tree and ducts and is used if ultrasound is inconclusive or if ductal stones are suspected without intervention, but it’s not the first-line test due to cost and availability. Barium swallow is unrelated to biliary pathology.