Assessment of Endoscopic Mucosal Healing of Ulcerative Colitis Using Linked Colour Imaging, a Novel Endoscopic Enhancement System

Background and aims: Mucosal healing and control of intestinal mucosal inflammation are important treatment goals for maintaining clinical remission in ulcerative colitis [UC] patients. Here, we investigated the efficacy of linked colour imaging [LCI], a novel endoscopic enhancement system, for diagnosing mucosal inflammation in UC patients.

Methods: All examinations were carried out with a LASEREO endoscopic system [FUJIFILM Co., Tokyo, Japan]. Fifty-two patients with UC were enrolled, and 193 areas assessed by LCI were examined. LCI patterns were classified as; A, no redness; B, redness with visible vessels; and C, redness without visible vessels. Regions of interest [ROIs] were set at biopsy sites, and the red colour in the ROI was calculated from the Commission internationale de l'éclairage [CIE] color space and digitized [LCI-index]. Biopsy specimens were taken at each ROI and evaluated with Matts histopathological grade. Thirty months was defined as the time interval between endoscopic diagnosis and relapse of UC.

Results: Interobserver agreement for LCI classification was excellent between an expert and non-experts. Among areas with a Mayo endoscopic subscore of 0, 41.8% and 4.6% were classified as LCI-B and LCI-C, respectively. Among areas with a Mayo endoscopic subscore of 1, 60.5% and 34.6% were classified as LCI-C and LCI-B, respectively. The LCI index strongly correlated with the histopathological Matts score. Non-relapse rates significantly correlated with LCI classification [p = 0.0055], but not with Mayo endoscopic subscore [p = 0.0632].

Conclusion: Endoscopic LCI classification and LCI index can subdivide samples with the same Mayo endoscopic subscore. LCI may be a novel approach for evaluating colonic mucosal inflammation and for predicting outcome in UC patients.