Diagnosing Extrahepatic Bile Duct Stones Using Intraductal Ultrasonography: A Case Series

Abstract

Background and Study Aims: Intraductal ultrasonography (IDUS), a new ultrasonographic diagnostic procedure, was used to assess the presence of extrahepatic bile duct stones.

Patients and Methods: The IDUS apparatus consisted of a 6-French high-frequency (20 MHz) probe. Prior to clinical application, in-vitro studies were conducted in a water tank. Clinically, IDUS was successful in 31 patients after endoscopic retrograde cholangiography. Interpretations of IDUS images were evaluated in comparison with cholangiographic and fluoroscopic findings.

Results: Experimental testing demonstrated that stones or fragments were typically visualized as strong, high-echo images with acoustic shadowing; air bubbles were seen as fan-shaped high-echo areas or comet-shaped high-echo areas; and sludge was visualized as soft, easily changing, high-echo structures. Extrahepatic bile duct stones were visualized by IDUS in 30 of 31 patients (96.8 %), while fluoroscopy and cholangiography identified 19 (61.3 %) and 25 (80.6 %), respectively. Accurate differentiation between stones and air bubbles was also possible.

Conclusion: IDUS could be a useful modality in the diagnosis of extrahepatic bile duct stones.