Naito, Yuji

INTRODUCTION: Mucosal healing is a widely accepted target for ulcerative colitis (UC) treatment. Linked color imaging (LCI) is a novel endoscopic enhancement system that utilizes Light Emitting Diode (LED) sources to spectrally enhance subtle erythema and mucosal surface patterns which may improve endoscopic classification of IBD associated inflammation. We aimed to assess the accuracy of LCI in classifying UC-associated mucosal healing compared to a validated histological reference standard (Geboes score). METHODS: 22 patients with ulcerative colitis were prospectively enrolled and evaluated by LCI colonoscopy using the Fujifilm’s digital video Processor VP-7000 and LED light source BL-7000 (Fujifilm, Tokyo Japan). Interobserver agreement was reported as kappa values. Geboes score was reported as score range of 0 to 5.4. A Geboes score of ≥3.1 (presence of surface intraepithelial neutrophils or < 5% crypts) was used to define histologic activity and a score of < 2B (no increase in neutrophils in the lamina propria) was used to define histologic remission. Geboes score has been previously validated to predict clinical recurrence. We calculated the overall accuracy, positive predictive value (PPV) and negative predictive value (NPV) of the LCI classification identifying mucosal healing against the Geboes score using the Fisher’s exact test. RESULTS: Total of 62 endoscopic images were obtained for different parts of the colon, 43 of which were matched to a corresponding biopsy. Endoscopic images were scored by 2 endoscopists into LCI-A (no redness), LCI-B (redness with visible vessels) and LCI-C (redness without visible vessels). A final LCI score was given for images with discrepant scores based on a consensus vote from both endoscopists. The interobserver agreement between the two endoscopists was 81%, kappa of 0.71 (95% confidence interval [CI] 0.57- 0.86). Among regions scored ≥3.1 on Geboes score, 9.5%, 28.6% and 61.9 % were classified as LCI-A, LCI-B and LCI-C, respectively ( P < 0.0001). Among images scored < 2B on Geboes score, 81.8%, 13.6% and 4.6% were classified as LCI-A, LCI-B and LCI-C, respectively ( P < 0.0001). Analyzing data against histology with LCI-A representing mucosal healing and LCI-B and C representing active mucosal disease, the overall accuracy becomes 86%, with NPV of 82.6% and PPV of 90% for identifying UC patients with histological and endoscopic evidence of mucosal healing. CONCLUSION: LCI technology has a potential role in assessing mucosal healing in UC.