Linked color imaging (LCI) was recently developed and uses a laser endoscopic system (Fujifilm Co, Tokyo, Japan) that acquires images by simultaneously using narrow-band short-wavelength light and white-light (WL) in an appropriate balance. LCI is a new image-enhancing technology that is intended to enhance slight color differences in the red region of the mucosa. The acquired color information is reallocated to differentiate colors that are similar to the mucosal color, resulting in improved performance in depicting blood vessels, and additional image processing that enhances color separation for red color permits clear visualization of red blood vessels and white pits. This modality may increase the detection rate of colorectal polyps by enhancing the visibility of colonic mucosal vessels. In addition, it has been reported that LCI increases the visibility of colorectal flat lesions and contributes to improvement of the detection rate for these lesions. The primary aim of the current study was to compare the detection rate of colorectal flat lesions of LCI cap-assisted colonoscopy with WL cap-assisted colonoscopy in prospective randomized trial. In addition, we prospectively compared LCI and WL with regard to the visibility of colorectal flat lesions found in this study.

Inclusion Criteria:

• We enrolled consecutive patients who were referred for colonoscopy to our hospital for diagnostic work up of colonic symptoms, surveillance of colorectal polyps, and colorectal cancer screening.

Exclusion Criteria:

• familial colorectal cancer syndrome including familial adenomatous polyposis and hereditary non-polyposis colorectal cancer syndrome, personal history of colorectal cancer or inflammatory bowel disease and those who had previous colonic resection.

Patients who were considered to be unsafe for polypectomy, including patients with bleeding tendency and those with severe comorbid illnesses, were excluded. Those in whom <90% of mucosa was seen due to mixture of semisolid and solid colonic contents were also excluded because of poor bowel preparation.