COLONIC POLYP DIFFERENTIATION USING TIME-RESOLVED AUTOFLUORESCENCE SPECTROSCOPY

Background: Steady-state autofluorescence spectroscopy has been examin ed previously as a technique for distinguishing polyp types during col onoscopy. 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-re solved autofluorescence spectroscopy in vivo and to determine the diag nostic accuracy of the technique as applied to colonic dysplasia. Meth ods: A time-resolved spectrometer was used to measure the spectrally r esolved transient decay of laser-induced autofluorescence emission fro m 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 measu red decay time provided a means of distinguishing adenomas from non-ad enomas with a sensitivity of 85%, a specificity of 91%, a positive pre dictive value of 92%, and a negative predictive value of 83%. Conclusi ons: Time-resolved autofluorescence spectroscopy is a promising optica l diagnostic technique for determining polyp types in vivo.