Narrow Band Imaging Versus Artificial Intelligence for Colonic Surveillance in Inflammatory Bowel Disease: a Prospective, Randomized, Crossover Study The CLEAR-IBD Trial (Colorectal Lesion Evaluation Assisted by Real-time AI in Inflammatory Bowel Disease)

Background and Rationale

Patients with inflammatory bowel disease (IBD) remain at increased risk of colorectal cancer (CRC) compared with the general population, and colonoscopic surveillance has been shown to reduce both CRC incidence and CRC-related mortality. Although high-definition dye-based chromoendoscopy is recommended by most guidelines as the surveillance technique of choice, its uptake remains limited due to training requirements, added procedure time, and cost. As a result, several guidelines continue to accept virtual chromoendoscopy techniques, including narrow-band imaging (NBI), and high-definition white-light endoscopy as alternatives.

Computer-aided detection (CADe) systems based on artificial intelligence have demonstrated meaningful improvements in adenoma and polyp detection in non-IBD populations. However, the convolutional neural network-based algorithms underlying these systems have largely been trained on datasets that excluded patients with IBD, so the real-world performance of currently available non-IBD-trained CADe systems for detecting colitis-associated dysplasia remains unknown. Existing evidence in this area has relied mainly on retrospective analyses of still-image datasets, without prospective, real-time comparison against validated comparators such as chromoendoscopy or NBI. A direct, prospective comparison is therefore needed.

Study Design This is a unicentric, two-arm, open-label, randomized, crossover clinical trial conducted at the IBD Clinic of the Gastroenterology Department, Vall d'Hebron University Hospital, Barcelona, Spain. Each participant undergoes a single colonoscopy in which the entire colon is examined twice, consecutively, by two different endoscopists using the two study techniques (CADe and NBI) in randomized order, allowing each patient to act as their own control and minimizing between-patient confounding.

Study Procedures Each participant is examined on the same day by two endoscopists with expertise in IBD endoscopic surveillance. Endoscopist 1 examines the entire colon using either AI (ENDO-AID CADe System, Olympus, Tokyo, Japan) or NBI, per the randomization sequence. Before lesion assessment, endoscopic remission is confirmed using the Mayo endoscopic score (UC) or the Simple Endoscopic Score for Crohn's Disease (SES-CD), requiring a score of 0. Lesions identified are documented and managed accordingly (resection or biopsy). Endoscopist 2, blinded to the findings of Endoscopist 1, re-examines the entire colon using the alternate technique, documents any additional findings, and manages any lesions missed during the first examination. Both endoscopists perform an equal number of examinations with each technique as the first or second pass, and all procedures use the same high-definition endoscope and processor (Olympus CF-HQ190L, EVIS X1).