Cholangioscopy-guided ERCP: expanding diagnostic and therapeutic applications

Endoscopic retrograde cholangiopancreatography (ERCP) remains a cornerstone technique for the management of pancreaticobiliary diseases, but conventional ERCP relies largely on fluoroscopic images and cannot directly evaluate intraductal mucosal abnormalities. Cholangioscopy has expanded the diagnostic and therapeutic scope of ERCP by enabling direct visualization of the biliary tree, targeted tissue acquisition, and visual control of intraductal interventions. The technology has evolved from early dual-operator mother-baby systems to single-operator cholangioscopy, high-resolution digital disposable platforms, direct peroral cholangioscopy using ultraslim endoscopes, and emerging systems such as EyeMax/EYEMAX with larger working channels and improved intraductal access. Clinically, cholangioscopy-guided ERCP is most established for indeterminate biliary strictures and difficult bile duct stones. In indeterminate strictures, cholangioscopy should be interpreted within a multimodality diagnostic framework that includes cross-sectional imaging, conventional ERCP-based sampling, endoscopic ultrasound-guided tissue acquisition, and cholangioscopy-guided visual assessment and biopsy. In difficult stones, cholangioscopy-guided electrohydraulic or laser lithotripsy improves targeted fragmentation and duct clearance when conventional ERCP techniques fail. Emerging applications include assessment of intraductal papillary neoplasms of the bile duct, screening or surveillance of risk-enriched intraductal neoplasms, primary sclerosing cholangitis-associated strictures, post-transplant biliary complications, complex stent guidance, and selected gallbladder interventions. This review summarizes the evolution of cholangioscopy technology, procedural considerations, current evidence, clinical outcomes, safety issues, and future directions including image-enhanced endoscopy and artificial intelligence-assisted image interpretation.