Indeterminate biliary stricture remains a significant diagnostic challenge. The current method of ERCP with bile duct brush cytology has substantial room for improvement. We aimed to determine the efficacy of a digital single-operator cholangioscopy (DSOC) in evaluation of indeterminate biliary stricture.

An observational cohort study was conducted among the patients who underwent DSOC for the indication of indeterminate biliary stricture at a tertiary academic medical center. The outcomes of interests were the accuracy of DSOC in visual interpretation and bile duct sample and identification of any factor(s) that could influence its effectiveness.

One hundred five patients were included. The overall accuracy of DSOC in visual interpretation was 89.5%, whereas the accuracy of bile duct sample was 83.2%. The sensitivities of visual impression and bile duct sample were 89.1% and 69.8% and their specificities were 90% and 97.9%, respectively. The degree of endoscopists' experience with fewer than 25 cases and the severity of hyperbilirubinemia negatively impacted the accuracy of DSOC. Among 55 patients with definitive diagnosis of malignant stricture, the sensitivity of combined intraductal forceps biopsy sampling and brush cytology was 80.6%, whereas the sensitivity of brush cytology alone was 47.1%.

DSOC augments ERCP in evaluating indeterminate biliary stricture. The acquisition of intraductal forceps biopsy samples should be a requisite in evaluation of indeterminate biliary stricture with DSOC. Discovery of modifiable factors such as the degree of endoscopists’ expertise and the severity of hyperbilirubinemia, which can influence the accuracy of DSOC, warrants further studies on patient preprocedure optimization and an endoscopic training program that will cultivate procedural competency.