The Role of Endoscopic Ultrasound in Detecting Common Bile Duct  Stones Missed Post-Endoscopic Retrograde Cholangiopancreatography in Patients with Calculous Obstructive Jaundice

Background Choledocholithiasis occurs in up to 20% of patients with gallstones. Diagnosing choledocholithiasis can be challenging. Previously, the gold standard for diagnosis was endoscopic retrograde cholangiopancreatography (ERCP). However, small stones often evade detection through ERCP and magnetic resonance cholangiopancreatography (MRCP). Endoscopic ultrasound (EUS) has proven effective in identifying common bile duct (CBD) stones that MRCP and ERCP might miss, particularly small stones or those lodged in the distal CBD or papillary region. The study aimed to evaluate the accuracy of EUS in detecting CBD stones missed by MRCP and ERCP. Methods A case-control study was conducted; we enrolled 30 patients who were presented with calculous obstructive jaundice and had undergone both ERCP and MRCP. A stent was inserted in these patients. Prior to stent removal, these patients underwent EUS to evaluate its effectiveness in detecting any remaining CBD stones post-ERCP. The sensitivity and specificity of EUS, ERCP, and MRCP were compared based on the presence, size, and number of detected stones. Results The mean age of involved patients was 50.3 ± 10.2 years. ERCP demonstrated a sensitivity of 44.4%, specificity of 100%, positive predictive value (PPV) of 100%, negative predictive value (NPV) of 16.6%, and an accuracy of 50%. MRCP showed a sensitivity of 81.5%, specificity of 100%, PPV of 100%, NPV of 37.5%, and an accuracy of 83.3% when compared to EUS results. The complication rate for EUS was significantly lower than that for diagnostic ERCP. Additionally, an EUS-based strategy was more cost-effective than diagnostic ERCP for patients with low, moderate, or intermediate risk. Conclusion Endoscopic ultrasound (EUS) is a promising, non-invasive, non-contrast technique that may serve as a superior diagnostic tool compared to MRCP and ERCP, particularly for detecting small stones or those impacted in the distal CBD or papillary region.