Background and study aims: Biliary endoscopic ultrasonography (EUS) and endoscopic retrograde cholangiography (ERC) are equally accurate for the diagnosis of common bile duct (CBD) stone. The aim of this prospective 1-year follow-up study was to determine whether normal findings at initial EUS obviated the need for ERC.
Patients and methods: During a 17-month period, all patients referred for biliary EUS because of suspicion of CBD stone, in whom EUS findings were normal were included in the study. Early (1-month) and late (1-year) follow-up details were obtained by mail or telephone. The clinical course and need for ERC were recorded.
Results: 238 patients were enrolled. During follow-up, 59 (25 %) patients underwent cholecystectomy, with (n=31) or without (n=28) cholangiography, and 30 patients underwent ERC (13 %). CBD stone was found in 14 (6 %) patients. Of these 30 patients, ERC was done in 15 cases in the first week after EUS, because of persistent suspicion of a CBD stone which was found in 10 patients. The 15 late ERC procedures (carried out more than 1 week after EUS) revealed only one CBD stone. The negative predictive value of EUS for the diagnosis of CBD stones was 95.4 %.
Conclusions: Patients with suspicion of CBD stones but normal EUS findings have a low risk of needing ERC in a 1-year period.