Colonoscopy is considered the gold standard for diagnosis of colonic polyps. However, it was reported that colonoscopy could still miss colonic polyps. Many attempts have been made to improve the detection rate of colonoscopy. Artificial intelligence (AI) is a promising new technique to improve detection rate of colonic adenoma. However, it remains uncertain whether whether the combined use of Endocuff and AI assisted examination could help to further improve the adenoma detection rate. This is a prospective randomized trial comparing the use of endocuff with AI, AI alone or conventional colonoscopy examination on adenoma detection rate.

TThis is a prospective randomized tandem colonoscopy trial comparing three different modes of colonoscopy techniques. The first group will use Endocuff (Olympus, Hong Kong) and AI assisted colonoscopy. The second group will use AI assisted colonoscopy alone and the third group will use standard high-definition white light colonoscopy.

Eligible patients will be randomly allocated in a 1:1:1 ratio to three groups. Patients will be stratified according to indications of colonoscopy (symptomatic vs screening/surveillance).

All examination will be performed with high-definition endoscopes (EVIS-EXERA 290 video system, Olympus Optical, Tokyo, Japan) under white light by experienced endoscopists. All endoscopists should have received training on the interpretation of real-time AI detection system as well as the Endocuff before performing study colonoscopy.

In all colonoscopy examination, colonoscope will be first advanced to the cecum as confirmed by identification of the appendiceal orifice and ileocecal valve or by intubation of the ileum. After cecal intubation is performed, the colonoscopy is first withdrawn according to the group assigned. For group 1, the first withdrawal would be done with Endocuff and AI assistance. For group 2, the first withdrawal would be done under AI assistance only. For group 3, the first withdrawal would be done under standard high definition colonoscopy only.

All detected polyps will be removed during the withdrawal only. The size (measured with biopsy forceps), location and morphology of each polyp will be recorded by an independent observer. The withdrawal time (minus the polypectomy site) will be measured by a stopwatch and with a minimum of 6 minutes. The bowel preparation quality will be graded according to the Boston Bowel Preparation Scale

Inclusion Criteria:

• All adult patients, aged 40 or above, undergoing outpatient colonoscopy in the Queen Mary Hospital, Tung Wah Hospital and Tuen Mun Hospital in Hong Kong will be recruited.

Exclusion Criteria:

• Patients will be excluded if they have history of inflammatory bowel disease, colorectal cancer, previous bowel resection, Peutz-Jeghers syndrome, familial adenomatous polyposis or other polyposis syndromes, bleeding tendency or severe comorbid illnesses for which polypectomy is considered unsafe. Moreover, after randomization, if the cecum could not be intubated for various reasons or Boston Bowel Preparation Scale (BBPS) score is <2, these patients will be excluded