Magnetic resonance cholangio-pancreatography versus endoscopic retrograde cholangio-pancreatography in the diagnosis of common bile duct stones: a prospective comparative study

Aim. As it is a non-invasive method, magnetic resonance cholangiography (MRCP) has almost completely replaced endoscopic retrograde cholangiography (ERCP) in the diagnosis of pancreato-biliary diseases. The aim of this study was to evaluate sensitivity, specificity, diagnostic accuracy, positive predictive value (PPV) and negative predictive value (NPV) of MRCP in diagnosis of choledocholithiasis using ERCP/endoscopic sphincterotomy (ES) as gold standard. Methods. For this study 140 individuals, suspected for lithiasis of the common bile duct (CBD), were enrolled. After a clinical and biochemical evaluation, patients underwent upper abdominal ultrasonography, then MRCP and diagnostic and/or operative ERCP. Results. Only 120 out of 140 patients completed the study. MRCP diagnosed lithiasis of CBD in 84. ERCP confirmed the lithiasis in 73/84 patients who were submitted to ES. Eleven were negative after ES. ERCP documented stones in 10 patients among the 36 negative at MRCP; stones were detected only in four patients after ES. In 26 out of 36 patients negative at MRCP, ERCP confirmed this response: only 12 out of 26 patients underwent ES. The sensitivity, specificity, diagnostic accuracy, PPV and NPV of MRCP were: 88%, 72%, 83%, 87%, 72%. Conclusion. As the MRCP diagnostic yield still limited with small stones, the question of which patient is the best candidate to ERCP/ES is still unsolved.