Advanced endoscopic imaging for biliary strictures: Review of current technologies

Conventional diagnostic techniques for indeterminate biliary strictures using endoscopic retrograde cholangiopancreatoscopy based ductal brushings and biopsy alone remains insensitive with inconsistent yields. There are multiple technologies, both established and novel, including peroral cholangioscopy, endoscopic and intraductal ultrasound, probe-based confocal laser endomicroscopy, and volumetric laser endomicroscopy with evolving data to support their use in the workup of indeterminate biliary strictures. Implementation of such technologies remains hindered by steep operator learning curves, device cost, and a dirth of comparative literature to support evidence based practice using one device over the other or adjunctively with the current gold standard of endoscopic retrograde cholangiopancreatoscopy. In this review, we focus on the aforementioned modalities, their technical specifications and operator considerations, and the available literature for use in evaluating indeterminate biliary strictures.