Development and Validation of a Deep Learning Algorithm to Evaluate Endoscopic Disease Activity of Ulcerative Colitis.

Inclusion Criteria: * Patients with ulcerative colitis undergoing colonoscopy Exclusion Criteria: * Known or suspected bowel obstruction, stricture or perforation * Compromised swallowing reflex or mental status * Severe congestive heart failure (New York Heart Association class III or IV) * Uncontrolled hypertension (systolic blood pressure \> 170 mm Hg, diastolic blood pressure \> 100 mm Hg) * Pregnancy or lactation * Hemodynamically unstable * Colonic surgery history * Bad bowel preparation (segmental BBPS\<2) * Unable to give informed consent