Development of Advanced Imaging Criteria for the Endoscopic Identification of Inflammatory Polyps

Inflammatory polyps (IPs) are frequently encountered at colonoscopy in inflammatory bowel disease (IBD) patients and are associated with an increased risk of colon cancer. The aim of this prospective endoscopic image review and analysis was to describe endoscopic features of IPs in IBD patients at surveillance colonoscopy and determine the ability to endoscopically discern IPs from other colon polyps using high-definition white light (WL), narrow band imaging with magnification (NBI), and chromoendoscopy (CE).

Digital images of IPs using WL, NBI, and CE were reviewed by four attending gastroenterologists using a two-round modified Delphi method. The ability to endoscopically discern IPs from other colon polyps was determined among groups of gastroenterology fellows and attendings. IPs were classified by gross appearance, contour, surface pattern, pit pattern, and appearance of surrounding mucosa in IPs, as well as accuracy of diagnosis.

Features characteristic of IPs included a fibrinous cap, surface friability and ulceration, an appendage-like appearance, the halo sign with CE, and a clustering of a multiplicity of IPs. The overall diagnostic accuracy for IP identification was 63% for WL, 42% for NBI, and 64% for CE. High degrees of histologic inflammation significantly improved the accuracy of diagnosis of IP with WL and CE, whereas the use of NBI significantly impaired IP accuracy.

The overall diagnostic accuracy when applying these criteria to clinical images was modest, with incremental benefit with addition of CE to WL. CE showed promise predicting IP histology in actively inflamed tissue. Institutional Review Board approval was obtained. ClinicalTrials.gov Identifier: NCT01557387.