Quantification of autofluorescence imaging can accurately and objectively assess the severity of ulcerative colitis.
OBJECTIVE
No endoscopic examination has been able to evaluate severity of ulcerative colitis (UC) by quantification. This prospective study investigated the efficacy of quantifying autofluorescence imaging (AFI) to assess the severity of UC, which captures the fluorescence emitted from intestinal tissue and then quantifies the intensity using an image-analytical software program.


METHODS
Eleven endoscopists separately evaluated 135 images of conventional endoscopy (CE) and AFI from a same lesion. A CE image corresponding to Mayo endoscopic subscore 0 or 1 was defined as being inactive. The fluorescence intensities of AFI were quantified using an image-analytical software program (F index; FI). Active inflammation was defined when Matts' histological grade was 2 or more. A cut-off value of the FI for active inflammation was determined using a receiver operating characteristic (ROC) analysis. The inter-observer consistency was calculated by unweighted kappa statistics.


RESULTS
The correlation coefficient for the FI was inversely related to the histological severity (r = -0.558, p < 0.0001). The ROC analysis showed that the optimal cut-off value for the FI for active inflammation was 0.906. The average diagnostic accuracy of the FI was significantly higher than those of the CE (84.7 vs 78.5 %, p < 0.01). The kappa values for the inter-observer consistency of CE and the FI were 0.60 and 0.95 in all participants, 0.53 and 0.97 in the less-experienced endoscopists group and 0.67 and 0.93 in the expert group, respectively.


CONCLUSIONS
The quantified AFI is considered to be an accurate and objective indicator that can be used to assess the activity of ulcerative colitis, particularly for less-experienced endoscopists.
Division of Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical University, 2-1 Midorigaoka-higashi, Asahikawa, Hokkaido, 078-8510, Japan.
Kentaro
K
Moriichi
Division of Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical University, 2-1 Midorigaoka-higashi, Asahikawa, Hokkaido, 078-8510, Japan. fjym@asahikawa-med.ac.jp.
Mikihiro
M
Fujiya
Division of Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical University, 2-1 Midorigaoka-higashi, Asahikawa, Hokkaido, 078-8510, Japan.
Masami
M
Ijiri
Division of Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical University, 2-1 Midorigaoka-higashi, Asahikawa, Hokkaido, 078-8510, Japan.
Kazuyuki
K
Tanaka
Division of Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical University, 2-1 Midorigaoka-higashi, Asahikawa, Hokkaido, 078-8510, Japan.
Aki
A
Sakatani
Division of Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical University, 2-1 Midorigaoka-higashi, Asahikawa, Hokkaido, 078-8510, Japan.
Tatsuya
T
Dokoshi
Division of Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical University, 2-1 Midorigaoka-higashi, Asahikawa, Hokkaido, 078-8510, Japan.
Shugo
S
Fujibayashi
Division of Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical University, 2-1 Midorigaoka-higashi, Asahikawa, Hokkaido, 078-8510, Japan.
Katsuyoshi
K
Ando
Division of Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical University, 2-1 Midorigaoka-higashi, Asahikawa, Hokkaido, 078-8510, Japan.
Yoshiki
Y
Nomura
Division of Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical University, 2-1 Midorigaoka-higashi, Asahikawa, Hokkaido, 078-8510, Japan.
Nobuhiro
N
Ueno
Division of Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical University, 2-1 Midorigaoka-higashi, Asahikawa, Hokkaido, 078-8510, Japan.
Shin
S
Kashima
Division of Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical University, 2-1 Midorigaoka-higashi, Asahikawa, Hokkaido, 078-8510, Japan.
Takuma
T
Gotoh
Division of Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical University, 2-1 Midorigaoka-higashi, Asahikawa, Hokkaido, 078-8510, Japan.
Junpei
J
Sasajima
Division of Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical University, 2-1 Midorigaoka-higashi, Asahikawa, Hokkaido, 078-8510, Japan.|Digestive Disease Center, Asahikawa City Hospital, Asahikawa, Hokkaido, Japan.
Yuhei
Y
Inaba
Division of Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical University, 2-1 Midorigaoka-higashi, Asahikawa, Hokkaido, 078-8510, Japan.
Takahiro
T
Ito
Division of Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical University, 2-1 Midorigaoka-higashi, Asahikawa, Hokkaido, 078-8510, Japan.|Division of Gastroenterology, International University of Health and Wealfare Hospital, Nasushiobara, Tochigi, Japan.
Hiroki
H
Tanabe
Digestive Disease Center, Asahikawa City Hospital, Asahikawa, Hokkaido, Japan.
Yusuke
Y
Saitoh
Division of Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical University, 2-1 Midorigaoka-higashi, Asahikawa, Hokkaido, 078-8510, Japan.|Division of Gastroenterology, International University of Health and Wealfare Hospital, Nasushiobara, Tochigi, Japan.
Yutaka
Y
Kohgo
D003093:Colitis, Ulcerative / Q000175:diagnosis* / Q000473:pathology; D016099:Endoscopy, Gastrointestinal; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D061848:Optical Imaging; D011446:Prospective Studies; D012720:Severity of Illness Index
Autofluorescence imaging; Endoscopy; Ulcerative colitis