Transabdominal Ultrasonography in Symptomatic Choledocholithiasis – Usefulness in Settings with Limited Resources

Abstract

Objective: Ultrasonography remains the initial imaging modality in the management of biliary disease. This study is designed to evaluate the accuracy of transabdominal ultrasonography in diagnosing biliary pathology in patients with choledocholithiasis. Methods: This was a retrospective study of a continuous sample of patients over a period of 3 years ending in January 2016; these patients were referred for endoscopic management of choledocholithiasis to a tertiary care hospital in Colombo, Sri Lanka. Ultrasound reporting was carried out by different consultant radiologists at both the index and the referring hospitals. The findings of endoscopic retrograde cholangiograms were compared with the ultrasound scan (USS) results. Results: A total of 247 patients were included in the study. USS was 97.4% accurate in detecting intrahepatic duct dilatation (IHDD). Stone counts and the location of stone(s) in the USSs correlated strongly with the number of stones delivered during endoscopic removal and their location in cholangiograms (P < 0.001). The difference in mean diameter of the common bile duct (CBD) of patients with choledochal cysts (CCs) (18.57 mm) and of patients without them (12.39 mm) is statistically significant (P < 0.001). At 14.5 mm, the negative predictive value for a CC is 99.02%. Conclusion: Ultrasonography is a reliable tool in predicting IHDD, stone count, and the location of stones in the biliary tree, particularly in a resource-poor setting. A CBD diameter of 14.5 mm in transabdominal ultrasound scan can be used as a cutoff for predicting extrahepatic CC.