title: Evaluation of an enhanced digital film-duplication system by receiver operating characteristic analysis.
abstract: OBJECTIVE
  Over- or underexposure often results in poor quality radiographs. Using receiver operating characteristic analysis, the authors investigated the potential utility of a system that corrects densities in such images to improve the accuracy of lung nodule detection.
  
  
  METHODS
  Chest radiographs were digitized by a laser film digitizer. Simulated nodules were superimposed on 36 improperly exposed chest radiographs. All images, with and without nodules, were then processed by a nonlinear density-correction technique. Hard-copy images were produced by a laser film printer. Eight radiologists evaluated the corrected and uncorrected images for the presence or absence of lung nodules using a continuous (0-100) confidence-rating scale.
  
  
  RESULTS
  The detectability of lung nodules improved significantly in the retrocardiac/retrodiaphragmatic regions of underexposed images and in the peripheral lung region of overexposed images.
  
  
  CONCLUSIONS
  This system may increase diagnostic accuracy in detection of lung nodules in improperly exposed images.
authors.affiliation: Kurt Rossmann Laboratories for Radiologic Image Research, Department of Radiology, University of Chicago, IL 60637.
authors.forename: K R
authors.initials: KR
authors.lastname: Hoffmann
authors.forename: H
authors.initials: H
authors.lastname: MacMahon
authors.forename: K
authors.initials: K
authors.lastname: Doi
authors.forename: C E
authors.initials: CE
authors.lastname: Metz
authors.forename: L
authors.initials: L
authors.lastname: Yao
authors.forename: K
authors.initials: K
authors.lastname: Abe
mesh_terms: D016001:Confidence Intervals; D005069:Evaluation Studies as Topic; D005189:False Positive Reactions; D006801:Humans; D007834:Lasers; D008175:Lung Neoplasms / Q000000981:diagnostic imaging / Q000453:epidemiology; D008961:Models, Structural; D015588:Observer Variation; D012372:ROC Curve; D011856:Radiographic Image Enhancement / Q000295:instrumentation*; D013902:Radiography, Thoracic / Q000295:instrumentation* / Q000706:statistics & numerical data