title: Colonic polyp differentiation using time-resolved autofluorescence spectroscopy.
abstract: BACKGROUND
  Steady-state autofluorescence spectroscopy has been examined previously as a technique for distinguishing polyp types during colonoscopy. Although time-resolved methods have shown promise for tissue diagnosis in vitro, they have never been applied endoscopically. The aim of this study was to examine the feasibility of performing time-resolved autofluorescence spectroscopy in vivo and to determine the diagnostic accuracy of the technique as applied to colonic dysplasia.
  
  
  METHODS
  A time-resolved spectrometer was used to measure the spectrally resolved transient decay of laser-induced autofluorescence emission from colonic tissue in vivo.
  
  
  RESULTS
  Seventeen patients with 24 polyps (13 adenomatous, 11 non-adenomatous) were studied. The autofluorescence decay from adenomas was faster than that from non-adenomas. The measured decay time provided a means of distinguishing adenomas from non-adenomas with a sensitivity of 85%, a specificity of 91%, a positive predictive value of 92%, and a negative predictive value of 83%.
  
  
  CONCLUSIONS
  Time-resolved autofluorescence spectroscopy is a promising optical diagnostic technique for determining polyp types in vivo.
authors.affiliation: Department of Medical Services, Massachusetts General Hospital, Boston 02114, USA.
authors.forename: M A
authors.initials: MA
authors.lastname: Mycek
authors.forename: K T
authors.initials: KT
authors.lastname: Schomacker
authors.forename: N S
authors.initials: NS
authors.lastname: Nishioka
mesh_terms: D018256:Adenomatous Polyps / Q000175:diagnosis*; D003106:Colon / Q000473:pathology; D003111:Colonic Polyps / Q000175:diagnosis*; D020685:Colonoscopes; D003113:Colonoscopy / Q000379:methods*; D003937:Diagnosis, Differential; D004867:Equipment Design; D005240:Feasibility Studies; D006801:Humans; D007834:Lasers; D013050:Spectrometry, Fluorescence / Q000295:instrumentation / Q000379:methods*; D013997:Time Factors