title: Quantification of 5-aminolevulinic acid induced fluorescence improves the specificity of bladder cancer detection.
abstract: OBJECTIVE
  5-Aminolevulinic acid induced fluorescence endoscopy has outstanding sensitivity for detecting early stage bladder cancer. Nevertheless, a third of the lesions that show specific fluorescence are histologically benign. We decreased the false-positive rate of 5-aminolevulinic acid induced fluorescence endoscopy by incorporating protoporphyrin IX fluorescence quantification into the standard cystoscopy procedure.
  
  
  METHODS
  In 25 cases (53 biopsies) of a history of or suspicion for bladder cancer 5-aminolevulinic acid induced fluorescence endoscopy and fluorescence image quantification were performed. For fluorescence image quantification images obtained with a target integrating color charge-coupled device camera were digitized and stored in a personal computer. Red-to-blue ratios were calculated from fluorescence positive lesions and results were correlated with hematoxylin and eosin histology.
  
  
  RESULTS
  Malignant fluorescence positive lesions showed significantly stronger fluorescence intensity than fluorescing lesions with benign histology. A threshold was established that decreased the false-positive rate by 30% without affecting sensitivity.
  
  
  CONCLUSIONS
  Fluorescence image quantification is a new endoscopic method for objectively selecting multicolor fluorescence bladder lesion images for biopsy. It has the potential of eliminating human error by different surgeons with variable experience in fluorescence endoscopy.
authors.affiliation: Department of Urology and Laser Research Laboratory, Klinikum Grosshadern, Ludwig-Maximilians-University of Munich, Munich, Germany.
authors.forename: D
authors.initials: D
authors.lastname: Zaak
authors.forename: D
authors.initials: D
authors.lastname: Frimberger
authors.forename: H
authors.initials: H
authors.lastname: Stepp
authors.forename: S
authors.initials: S
authors.lastname: Wagner
authors.forename: R
authors.initials: R
authors.lastname: Baumgartner
authors.forename: P
authors.initials: P
authors.lastname: Schneede
authors.forename: M
authors.initials: M
authors.lastname: Siebels
authors.forename: R
authors.initials: R
authors.lastname: Knüchel
authors.forename: M
authors.initials: M
authors.lastname: Kriegmair
authors.forename: A
authors.initials: A
authors.lastname: Hofstetter
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000622:Aminolevulinic Acid; D002295:Carcinoma, Transitional Cell / Q000175:diagnosis*; D003558:Cystoscopy / Q000379:methods*; D005260:Female; D005453:Fluorescence; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000175:diagnosis; D017319:Photosensitizing Agents; D012680:Sensitivity and Specificity; D001749:Urinary Bladder Neoplasms / Q000175:diagnosis*
chemical_list: D017319:Photosensitizing Agents; D000622:Aminolevulinic Acid