title: Visualization of colorectal neoplasia by a second-generation autofluorescence imaging system.
abstract: OBJECTIVE
  Autofluorescence imaging (AFI) systems may allow better visualization of colorectal neoplasia than conventional methods. However, this is difficult to demonstrate objectively. Recently, a second-generation AFI system with a noise-reduction algorithm was developed. We aimed to objectively evaluate the visualization of colorectal neoplasia by using a second-generation AFI system and software to calculate the color-contrast index.
  
  
  METHODS
  We retrospectively reviewed 53 consecutive colorectal neoplasias examined using the second-generation AFI system. Color-contrast indices between the colorectal lesions and the surrounding normal mucosa in the WLI, AFI and NBI images were calculated. The WLI, AFI, NBI and CE images were also evaluated by endoscopists using questionnaire-based visualization scores.
  
  
  RESULTS
  The color-contrast index seen in the AFI images (33.74 ± 9.20) was significantly higher than that in either the WLI (11.14 ± 6.14) or NBI images (11.72 ± 7.12). There was no significant difference between the color-contrast indices of the WLI and NBI images. The mean AFI image visualization score (6.7 ± 1.8) was significantly higher than that of WLI (6.0 ± 1.7), and tended to be higher than that of the NBI images (6.1 ± 1.6) when assessed by less-experienced endoscopists.
  
  
  CONCLUSIONS
  This study objectively demonstrates that compared to WLI and NBI, the second-generation AFI system enables superior visualization of colorectal neoplasms. The visualization scores were higher for the AFI images when evaluated by less-experienced endoscopists. These results indicate that the second-generation AFI system may aid less-experienced endoscopists in the detection of colorectal neoplasia.
authors.affiliation: Department of Internal Medicine, Division of Gastroenterology and Hepatology, The Jikei University School of Medicine , Tokyo , Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Ide
authors.forename: Naoto
authors.initials: N
authors.lastname: Tamai
authors.forename: Hiroko
authors.initials: H
authors.lastname: Inomata
authors.forename: Tomohiko R
authors.initials: TR
authors.lastname: Ohya
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Aihara
authors.forename: Syoichi
authors.initials: S
authors.lastname: Saito
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Kato
authors.forename: Hisao
authors.initials: H
authors.lastname: Tajiri
mesh_terms: D000236:Adenoma / Q000473:pathology*; D000368:Aged; D000465:Algorithms; D002277:Carcinoma / Q000473:pathology*; D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000473:pathology*; D005260:Female; D006801:Humans; D007089:Image Enhancement; D007413:Intestinal Mucosa / Q000473:pathology; D008297:Male; D008875:Middle Aged; D061848:Optical Imaging; D012189:Retrospective Studies