title: Enhanced visibility of colonic neoplasms using formulaic ratio imaging of native fluorescence.
abstract: OBJECTIVE
  Colonoscopy is the preferred method for colon cancer screening, but can miss polyps and flat neoplasms with low color contrast. The objective was to develop a new autofluorescence method that improves image contrast of colonic neoplasms.
  
  
  METHODS
  We selected the three strongest native fluorescence signals and developed a novel method where fluorescence images are processed in a ratiometric formula to represent the likely cellular and structural changes associated with neoplasia. Native fluorescence images of fresh surgical specimens of the colon containing normal mucosa, polypoid and flat adenomas as well as adenocarcinoma were recorded using a prototype multi-spectral imager. Sixteen patients, with a mean age of 62 years (range 28-81) undergoing elective resection for colonic neoplasms were enrolled. High contrast images were seen with fluorescence from tryptophan (Tryp), flavin adenine dinucleotide (FAD) and collagen.
  
  
  RESULTS
  When the image intensity of Tryp was divided pixel by pixel, by the intensities of FAD and collagen, the resulting formulaic ratio (FR) images were of exceptionally high contrast. The FR images of adenomas and adenocarcinomas had increased Weber contrast.
  
  
  CONCLUSIONS
  FR imaging is a novel imaging process that represents the likely metabolic and structural changes in colonic neoplasia that produces images with remarkably high contrast.
authors.affiliation: Department of Medicine, College of Medicine, University of Arizona, Tucson, Arizona, 85724; Department of Biomedical Engineering, College of Engineering, University of Arizona, Tucson, Arizona, 85721; College of Optical Sciences, University of Arizona, Tucson, Arizona, 85721.
authors.forename: Bhaskar
authors.initials: B
authors.lastname: Banerjee
authors.forename: Nathaniel S
authors.initials: NS
authors.lastname: Rial
authors.forename: Timothy
authors.initials: T
authors.lastname: Renkoski
authors.forename: Logan R
authors.initials: LR
authors.lastname: Graves
authors.forename: Sirandon A H
authors.initials: SA
authors.lastname: Reid
authors.forename: Chengcheng
authors.initials: C
authors.lastname: Hu
authors.forename: Vassiliki L
authors.initials: VL
authors.lastname: Tsikitis
authors.forename: Valentine
authors.initials: V
authors.lastname: Nfonsom
authors.forename: Judith
authors.initials: J
authors.lastname: Pugh
authors.forename: Urs
authors.initials: U
authors.lastname: Utzinger
mesh_terms: D000230:Adenocarcinoma / Q000175:diagnosis*; D000236:Adenoma / Q000175:diagnosis*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003110:Colonic Neoplasms / Q000175:diagnosis*; D003113:Colonoscopy / Q000295:instrumentation / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D061848:Optical Imaging / Q000295:instrumentation / Q000379:methods*
keywords: cancer; colon; fluorescence; imaging; polyps