Digital cholangioscopy upgrades IOA, accuracy for biliary stricture assessment

Eight visual criteria, named the Monaco Classification, have been identified for biliary lesions on digital single-operator cholangioscopy (DSOC), according to a study. Using these criteria has improved the interobserver agreement (IOA) and diagnostic accuracy rate of DSOC compared with previous studies.

In this two-phase study, the authors sought to define terminology by consensus for the visual diagnosis of biliary lesions to develop a model that will enhance the diagnostic performance of DSOC.

During criteria identification (phase 1), 12 expert biliary endoscopists who were blinded to the final diagnosis reviewed video-cholangioscopy clips and consolidated visual criteria into the following categories: (1) stricture, (2) lesion, (3) mucosal features, (4) papillary projections, (5) ulceration, (6) abnormal vessels, (7) scarring, (8) pronounced pit pattern. During validation (phase 2), 14 expert endoscopists assessed IOA rate by reviewing DSOC clips using the eight criteria.

In phase 1, consensus for the visual findings were sorted into eight criteria (Monaco Classification): presence of stricture (frequency, 75 percent), presence of lesion type (frequency, 55 percent), mucosal features (frequency, 55 percent), papillary projections (frequency, 45 percent), ulceration (frequency, 42.5 percent), abnormal vessels (frequency, 10 percent), scarring (frequency, 40 percent), and pronounced pit pattern (frequency, 10 percent).

Based on visual impression alone, the accuracy on final diagnosis stood at 70 percent.

For the second phase, the IOA rate via the Monaco Classification criteria ranged from slight to fair. The presumptive diagnosis IOA was fair (κ=0.31, SE=0.02), while the overall diagnostic accuracy was 70 percent.