Background and study aims: Endoscopic ultrasonography (EUS) with radial scanning is an efficient diagnostic tool where there is suspicion of common bile duct (CBD) stones. Little is known about the use of linear EUS in this condition. The aim of this study was to evaluate the diagnostic efficiency of linear EUS in a large group of patients suspected to have bile duct stones, using endoscopic retrograde cholangiopancreatography (ERCP) with endoscopic sphincterotomy and exploration of the CBD using a Dormia basket, or surgical choledochotomy with choledochoscopy, as diagnostic "gold standards."
Patients and methods: 134 patients with clinical suspicion of CBD stones were included in the study and prospectively evaluated, using EUS, and ERCP with endoscopic sphincterotomy (127 patients), or choledochotomy with choledochoscopy where ERCP was unsuccessful (seven patients). EUS was done before ERCP using an echo endoscope (Pentax FG 32 UA; 5 - 7.5 MHz) and Hitachi EUB 405 ultrasound machine. ERCP was done using the TFJ 100 or TJ 20 Olympus duodenoscope. ERCP was carried out within a mean of 2 days after EUS. The longest time between EUS and ERCP was 3 days. The examiners were blinded to the results of the other method used.
Results: CBD stones were found in 91 (68 %) patients at ERCP with ES or at surgery. The correct diagnosis was established by EUS in 85 patients. The remaining 43 patients without CBD stones were correctly diagnosed in 41 cases by means of EUS, giving an accuracy of 94 %, sensitivity of 93 %, specificity of 93 %, a positive predictive value of 98 %, a negative predictive value of 87 %, and a Youden's index of 89 %.
Conclusions: Linear EUS is a fairly reliable method for the evaluation of patients with high suspicion for CBD stones. The usefulness of linear EUS in the evaluation of patients with low or moderate suspicion for CBD stones warrants further study.