ABSTRACT
Biliary strictures are considered indeterminate when evaluation with imaging and standard tissue sampling during endoscopic retrograde cholangiopancreatography (ERCP) are non-diagnostic. Standard tissue sampling techniques include cytologic brushings, with or without fluorescence in situ hybridization (FISH), and endoscopic intraductal biopsies. These strictures are often clinically suspicious for malignancy. The management of these patients can vary substantially and relies on an accurate diagnosis of the lesion. Unfortunately, despite numerous modalities, the sensitivity of existing tissue sampling techniques remains low and can lead to delays in diagnosis and the need for additional procedures. Cholangioscopy has emerged as a means to visually inspect and obtain image-guided biopsies of the lesion in question, with improved sensitivity as well as a high specificity and accuracy for diagnosing the etiology of indeterminate biliary strictures. The types of cholangioscopy systems and a summary of the pertinent literature are discussed in this review.