K. Uchiyama*, T. Takagi, Y. Toyokawa, Y. Hotta, M. Tanaka, Y. Naito, Y. Itoh
Kyoto Prefectural University of Medicine, Molecular Gastroenterology and Hepatology, Kyoto, Japan
Mucosal healing and control of intestinal mucosal inflammation have been reported as important treatment goals for maintaining clinical remission in ulcerative colitis (UC) patients. In this study, we investigated the availability and efficacy of linked colour imaging (LCI), a novel endoscopic enhancement system, for the diagnosis of mucosal inflammation in UC patients.
All examinations were carried out with an EG-L590WR endoscope and a LASEREO endoscopic system (FUJIFILM Co., Tokyo, Japan). Blue laser imaging-bright data were converted to LCI by image processing. The images were acquired for LCI by simultaneously irradiating narrow-band short wavelength light and white light in the blue laser imaging-bright mode. LCI reallocates the acquired colour information to improve the viewer’s ability to recognise slight differences in mucosal colour. That is, LCI simultaneously expands and reduces colour information so that a reddish colour becomes redder, and a whitish colour becomes whiter. The red colour inside a region of interest (ROI) in the mucosal image is digitised and evaluated by the pathological inflammation and endoscopic scores. Further, 19 patients with UC were enrolled in this study, and 61 areas were assessed by LCI, for which biopsy was performed and examined. The patterns of LCI were classified as A no redness, B redness (with visible vessels), and C: redness (vessels are not visible). Inflammation in the biopsy specimen was evaluated according to the 4 phases of Matts biopsy specimen classification. The ROI (40 × 40 pixels) was set at the location of the biopsy, and the red colour in the ROI was calculated as CIELAB and digitised.
The investigated areas were classified by LCI as A, B, and C in 28, 22, and 9 cases, respectively. In group A, 85.7% (24/28) of the biopsy specimens were diagnosed as Matts score 2, and 92% of the specimens showed an endoscopic Mayo score of 0. In group B, the corresponding proportions were 90.9% (20/22) and 77.3%, whereas in group C, 77.8% (7/9) of the biopsy specimens were diagnosed as Matts score 3, and all showed an endoscopic Mayo score of 1. Hence, the digitisation of LCI strongly correlated with the endoscopic Mayo score and pathological Matts score.
According to the LCI classification in this study, most cases in groups A and B were classified as endoscopic Mayo score 0, whereas group C comprised only cases of Mayo score 1. The digitisation of LCI appears to be an objective method for evaluating mucosal redness and is considered a practical approach for evaluate intestinal mucosal inflammation in UC patients.