title: Is autofluorescence imaging endoscopy useful for determining the depth of invasion in gastric cancer?
abstract: OBJECTIVE
  Newly developed autofluorescence (AF) imaging (AFI) endoscopy can detect AF emitted by the gastrointestinal wall and may reliably detect tumors or inflammation that block AF. However, the efficacy of AFI endoscopy has not been evaluated for diagnosing the depth of tumor invasion in gastric cancer.
  
  
  METHODS
  AF endoscopic images were split into three bands (R, G and B) and expressed as grayscale values. AF indices, defined as the ratio of the G band image grayscale value to that of the R band, were calculated preoperatively. Correlations of AF indices with invasion depth and tumor thickness were assessed. AF indices were calculated preoperatively for 72 gastric cancer lesions without ulceration in 67 patients. The invasion grade of the lesions was classified histologically into 5 groups: M, SM, MP, SS and SE.
  
  
  RESULTS
  The mean tumor AF indices for each depth stage were 0.99, 0.77, 0.75, 0.74 and 0.61, respectively. A statistically significant difference was found between group M and the other groups.
  
  
  CONCLUSIONS
  AFI endoscopy may reliably determine the depth of gastric cancer tumor invasion, although an expanded study comprised of larger numbers of subjects and different types of cancers may be required to clearly demonstrate its validity.
authors.affiliation: 2nd Department of Internal Medicine, Shimane University, School of Medicine, Izumo, Japan.
authors.forename: Aya
authors.initials: A
authors.lastname: Otani
authors.forename: Yuji
authors.initials: Y
authors.lastname: Amano
authors.forename: Kenji
authors.initials: K
authors.lastname: Koshino
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Takahashi
authors.forename: Yuko
authors.initials: Y
authors.lastname: Mishima
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Imaoka
authors.forename: Ichiro
authors.initials: I
authors.lastname: Moriyama
authors.forename: Norihisa
authors.initials: N
authors.lastname: Ishimura
authors.forename: Shunji
authors.initials: S
authors.lastname: Ishihara
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Kinoshita
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D016099:Endoscopy, Gastrointestinal / Q000379:methods*; D005260:Female; D005453:Fluorescence; D006801:Humans; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness / Q000473:pathology*; D010865:Pilot Projects; D012372:ROC Curve; D018709:Statistics, Nonparametric; D013274:Stomach Neoplasms / Q000473:pathology*; D013552:Swine