The Detection of Bile Duct Stones in Suspected Biliary Pancreatitis: Comparison of MRCP, ERCP, and Intraductal US

Abstract

Early ERCP and endoscopic sphincterotomy for stone extraction can benefit the prognosis in patients with severe biliary pancreatitis, but are associated with complications. The ability to identify choledocholithiasis by noninvasive means in biliary pancreatitis is limited. The aim of this study was evaluation of the ability of MRCP to detect choledocholithiasis in patients with acute biliary pancreatitis. In addition, we investigated whether intraductal US (IDUS) could help manage these patients. Thirty-two patients with suspected biliary pancreatitis were studied prospectively. MRCP was performed immediately before ERCP by separate blinded examiners within 24 h of admission. Wire-guided IDUS was performed during ERCP within 72 h of admission, regardless of the results of MRCP. Using endoscopic extraction of a stone as the reference standard, the diagnostic yield of MRCP was compared with transabdominal US, CT, ERCP, and IDUS. The sensitivity of US, CT, MRCP, ERCP, and IDUS for identifying choledocholithiasis was 20.0%, 40.0%, 80.0%, 90.0%, and 95.0%, respectively. The overall agreement between MRCP and ERCP was 90.6% for choledocholithiasis (kappa= 0.808, p < 0.01). The sensitivity of MRCP for detecting choledocholithiasis decreased with dilated bile ducts (bile duct diameter > 10 mm, 72.7% vs 88.9%). The combination of ERCP and IDUS improved accuracy in the diagnosis of choledocholithiasis. MRCP can be used to select patients with biliary pancreatitis who require ERCP. IDUS may be applied in the management of biliary pancreatitis if ERCP is performed.