title: Detecting field cancerization using a hyperspectral imaging system.
abstract: BACKGROUND
  Field cancerization denotes subclinical abnormalities in a tissue chronically exposed to UV radiation. These abnormalities can be found surrounding the clinically visible actinic keratoses.
  
  
  OBJECTIVE
  The aim of this study was to test the feasibility of a hyperspectral imaging system in the detection of multiple clinical and subclinical AKs for early treatment of the affected areas.
  
  
  METHODS
  Altogether 52 clinical AKs in 12 patients were included in this study. In six patients digital photos were taken of the naive AKs, and again after methylaminolevulinate(MAL)-fluorescence diagnosis which was used to teach HIS to find subclinical lesions. After 2-3 days when the MAL had vanished, the hyperspectral images were taken. Biopsies were taken from clinical AKs, healthy-looking skin and several suspected subclinical AKs. In the other six patients digital and hyperspectral images were taken of the naive AKs followed by one biopsy per patient.
  
  
  RESULTS
  HIS detected all clinically visible 52 AKs and numerous subclinical lesions. The histopathology of the 33 biopsied lesions were concordant with the HIS results showing either AK (n = 28) or photodamage (n = 5). Of the 28 histopathologically confirmed AKs, 16 were subclinical. A specific diffuse reflectance spectrum of an AK and healthy skin was defined.
  
  
  CONCLUSIONS
  The hyperspectral imaging system offers a new, non-invasive method for early detection of field cancerization. Lasers Surg. Med. 45:410-417, 2013. © 2013 Wiley Periodicals, Inc.
authors.affiliation: Department of Dermatology and Allergology, Päijät-Häme Social and Health Care Group, Lahti, Finland; Department of Mathematical Information Technology, University of Jyväskylä, Jyväskylä, Finland.
authors.forename: Noora
authors.initials: N
authors.lastname: Neittaanmäki-Perttu
authors.forename: Mari
authors.initials: M
authors.lastname: Grönroos
authors.forename: Taneli
authors.initials: T
authors.lastname: Tani
authors.forename: Ilkka
authors.initials: I
authors.lastname: Pölönen
authors.forename: Annamari
authors.initials: A
authors.lastname: Ranki
authors.forename: Olli
authors.initials: O
authors.lastname: Saksela
authors.forename: Erna
authors.initials: E
authors.lastname: Snellman
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000622:Aminolevulinic Acid / Q000031:analogs & derivatives*; D058070:Asymptomatic Diseases; D001706:Biopsy; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D055623:Keratosis, Actinic / Q000175:diagnosis* / Q000473:pathology; D008297:Male; D062048:Narrow Band Imaging / Q000379:methods*; D010781:Photography; D017319:Photosensitizing Agents; D010865:Pilot Projects; D012867:Skin / Q000473:pathology
chemical_list: D017319:Photosensitizing Agents; C475457:methyl 5-aminolevulinate; D000622:Aminolevulinic Acid
keywords: actinic keratosis; field cancerization; hyperspectral imaging