The Role of Endoscopic Ultrasonography and Magnetic Resonance Cholangiopancreatography in Patients with Acute Pancreatitis after Negative Computed Tomography Findings of the Etiology

Objectives We aimed to investigate the roles of endoscopic ultrasonography (EUS) and magnetic resonance cholangiopancreatography (MRCP) in detecting the causes of acute pancreatitis after negative computed tomography (CT) findings. Methods Demographic characteristics, blood test results, the severity of pancreatitis, and definite or possible etiology of pancreatitis by EUS and MRCP were evaluated prospectively in 65 consecutively admitted patients after negative CT findings. Results Endoscopic ultrasonography and/or MRCP confirmed the definite causes of pancreatitis in 47.7% (31/65) (choledocholithiasis, 25; pancreatic divisum, 3; pancreatic cancer, 1; and pancreatic intraductal papillary mucinous neoplasm, 1). The possible causes were cholelithiasis in 75.4%, pancreaticobiliary common channel (PBCC) in 70.8%, and both in 89.2%. The diagnostic values of EUS were higher than MRCP for choledocholithiasis (35.4% vs 12.3%, P < 0.05). Cholelithiasis and the common bile duct diameter were independent factors for the definite etiology of acute pancreatitis. Choledocholithiasis was inversely associated with PBCC, and the common bile duct diameter was the only independent factor associated with PBCC. Conclusions Endoscopic ultrasonography is a useful imaging modality for detecting definite or possible causes of acute pancreatitis. A PBCC as well as biliary lithiasis could be not uncommon causes of acute pancreatitis after negative CT findings.