24 A Comparison of EUS and MRCP to Diagnose Choledocholithiasis

Abstract

INTRODUCTION: ASGE recommends EUS or MRCP for patients at intermediate risk for choledocholithiasis. Numerous studies have compared diagnostic yield of EUS and MRCP for choledocholithiasis. Two systematic reviews showed no significant difference in the two modalities. Diagnostic yield of both modalities is high for large stones. However, EUS is more sensitive in diagnosing small stones. METHODS: This is a retrospective study that includes the patients who had ERCP for suspected choledocholithiasis. Basic demographics, clinical, laboratory, imaging and endoscopic data was collected. The imaging modalities including abdominal ultrasound, CT, MRCP and EUS were compared using choledocholithiasis on ERCP as the gold standard. Performance characteristics such as sensitivity, specificity, positive predictive value, negative predictive value, positive and negative likelihood ratio and accuracy were calculated. RESULTS: During the study period, a total of 137 patients had ERCP for suspected choledocholithiasis. The mean age (±SD) was 53 ± 21 years. 81 (59%) were female and 78 (56.9%) were African American. 60 (43.8%) had EUS, 50 (36.5%) had MRCP, 74 (54%) had CT abdomen, 120 (87.6%) had abdominal ultrasound. Sensitivity, specificity, PPV, NPV, positive likelihood ratio, negative likelihood ratio and accuracy for EUS vs MRCP were 90 vs 85, 46 vs 78, 88 vs 95, 50 vs 54, 1.65 vs 3.84, 0.22 vs 0.19, 82 vs 84, respectively. CONCLUSION: The diagnostic yield of EUS and MRCP is high and comparable. Preference for EUS or MRCP may depend on availability, patient preference and probability of choledocholithiasis. Specificity and NPV of both modalities were low for detecting sludge. ERCP may be helpful in these cases if clinical suspicion for choledocholithiasis remains high.