Brief Article
Copyright ©2011 Baishideng Publishing Group Co., Limited. All rights reserved.
World J Gastroenterol. Dec 14, 2011; 17(46): 5110-5116
Published online Dec 14, 2011. doi: 10.3748/wjg.v17.i46.5110
Autofluorescence imaging endoscopy for identification and assessment of inflammatory ulcerative colitis
Taro Osada, Atsushi Arakawa, Naoto Sakamoto, Hiroya Ueyama, Tomoyoshi Shibuya, Tatsuo Ogihara, Takashi Yao, Sumio Watanabe
Taro Osada, Naoto Sakamoto, Tomoyoshi Shibuya, Tatsuo Ogihara, Sumio Watanabe, Department of Gastroenterology, Juntendo University School of Medicine, 113-8421 Tokyo, Japan
Atsushi Arakawa, Hiroya Ueyama, Takashi Yao, Department of Human Pathology, Juntendo University School of Medicine, 113-8421 Tokyo, Japan
Author contributions: Osada T conceived and designed the study; Osada T, Arakawa A, Sakamoto N, Ueyama H, Shibuya T and Ogihara T collected the data; Osada T, Yao T and Watanabe S interpreted the data; Osada T wrote the manuscript; all authors discussed the results and commented on the manuscript; Watanabe S gave final approval of this article.
Correspondence to: Taro Osada, MD, PhD, Department of Gastroenterology, Juntendo University School of Medicine, 2-1-1 Hongo, Bunkyo-ku, 113-8421 Tokyo, Japan. otaro@juntendo.ac.jp
Telephone: +81-3-58021060 Fax: +81-3-38138862
Received: February 16, 2011
Revised: August 4, 2011
Accepted: August 15, 2011
Published online: December 14, 2011
Abstract

AIM: To validate the clinical relevance of autofluorescence imaging (AFI) endoscopy for the assessment of inflammatory ulcerative colitis (UC).

METHODS: A total of 572 endoscopic images were selected from 42 UC patients: 286 taken with white light imaging (WLI) and 286 with AFI from the same sites. WLI images were assessed for overall mucosal inflammation according to Mayo endoscopic subscore (MES), and for seven characteristic endoscopic features. Likewise, AFI photographs were scored according to relative abundance of red, green and blue color components within each image based on an RGB additive color model. WLI and AFI endoscopic scores from the same sites were compared. Histological evaluation of biopsies was according to the Riley Index.

RESULTS: Relative to red (r = 0.52, P < 0.01) or blue (r = 0.56, P < 0.01) color component, the green color component of AFI (r = -0.62, P < 0.01) corresponded more closely with mucosal inflammation sites. There were significant differences in green color components between MES-0 (0.396 ± 0.043) and MES-1 (0.340 ± 0.035) (P < 0.01), and between MES-1 and ≥ MES-2 (0.318 ± 0.037) (P < 0.01). The WLI scores for “vascular patterns” (r = -0.65, P < 0.01), “edema” (r = -0.62, P < 0.01), histology scores for “polymorphonuclear cells in the lamina propria” (r = -0.51, P < 0.01) and “crypt architectural irregularities” (r = -0.51, P < 0.01) showed correlation with the green color component of AFI. There were significant differences in green color components between limited (0.399 ± 0.042) and extensive (0.375 ± 0.044) (P = 0.014) polymorphonuclear cell infiltration within MES-0. As the severity of the mucosal inflammation increased, the green color component of AFI decreased. The AFI green color component was well correlated with the characteristic endoscopic and histological inflammatory features of UC.

CONCLUSION: AFI has application in detecting inflammatory lesions, including microscopic activity in the colonic mucosa of UC patients, based on the green color component of images.

Keywords: Autofluorescence imaging endoscopy, Endoscopic activity, Histological activity, Microscopic inflammation, Green color component