title: Where's the naevus? Inter-operator variability in the localization of melanocytic lesion border.
abstract: BACKGROUND
  The first step in the analysis of a dermatoscopically imaged melanocytic lesion is segmentation--informally, isolating those points in the image belonging to the lesion from those belonging to the surrounding non-lesional skin. Although typically studied in the context of automated analysis, segmentation is a necessary step even for human operators who plan to evaluate quantitative features of a lesion (such as diameter or asymmetry).
  
  
  METHODS
  In a double blind evaluation of the segmentation of 77 digital dermatoscopic images, we observed a significant inter-operator variability.
  
  
  RESULTS
  The area of the disagreement region was on average 15.28% of the area of the lesion itself, and in 10% of the cases it was more than 28%. More experienced dermatologists showed greater agreement among themselves than with less experienced dermatologists, and a slight tendency toward 'tighter' segmentations.
  
  
  CONCLUSIONS
  The evaluation methodology addresses a number of crucial difficulties encountered in previous studies and may be of independent interest. Our results underscore the necessity of taking into account inter-operator variability in large epidemiological studies, in particular those involving less experienced dermatologists, and of striving toward techniques allowing greater standardization and replicability in the evaluation of the fundamental visual parameters of lesions.
authors.affiliation: Unit of Dermatology, Department of Pediatrics, University of Padua, Padua, Italy. belloni@pediatria.unipd.it
authors.forename: Anna Belloni
authors.initials: AB
authors.lastname: Fortina
authors.forename: Enoch
authors.initials: E
authors.lastname: Peserico
authors.forename: Alberto
authors.initials: A
authors.lastname: Silletti
authors.forename: Edoardo
authors.initials: E
authors.lastname: Zattra
mesh_terms: D046169:Dermoscopy / Q000379:methods*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D009508:Nevus, Pigmented / Q000473:pathology*; D015588:Observer Variation; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted; D012878:Skin Neoplasms / Q000473:pathology*