title: Comparison of radiologist and CAD performance in the detection of CT-confirmed subtle pulmonary nodules on digital chest radiographs.
abstract: OBJECTIVE
  Detection of subtle pulmonary nodules on digital radiography is a challenging task for radiologists. The aim of this study was to evaluate the performance of a newly approved computer aided detection (CAD) system.
  
  
  METHODS
  The sensitivity of 3 radiologists and of a CAD system for the detection of pulmonary nodules from 5 to 15 mm in size on digital chest radiography of 117 patients was compared. The reference standard was established by consensus reading of computed tomography scans by 2 experienced radiologists. Computed tomography scans and chest radiographs were performed within 4 weeks. Sixty-six pulmonary nodules from 42 patients, with a mean nodule diameter of 7.5 mm (standard deviation: 2.2 mm), were included in the statistical analysis. Seventy-five of the 117 patients did not have nodules from 5 to 15 mm of size.
  
  
  RESULTS
  Two hundred and eighty-eight false-positive detections of the CAD system were found with an average of 2.5 false-positives per image. Sensitivity of the CAD system was 39.4% (95% confidence interval: 11.8%), when compared with 18.2% to 30.3% (95% confidence interval 9.3% to 11.1%) of the 3 radiologists. Substantial agreement for nodule detection ([kappa]N: 0.64-0.73) was found among the 3 radiologists, whereas only moderate agreement was found between the radiologists and the CAD performance ([kappa]N: 0.45-0.52).
  
  
  CONCLUSIONS
  The CAD system's diagnostic sensitivity in detecting pulmonary nodules of 5 to 15 mm of size was superior to the 1 of radiologists. The CAD system may be used for assisting the radiologist in the detection of lung nodules on digital chest radiographs.
authors.affiliation: Department of Diagnostic Radiology, University Hospital Freiburg, Freiburg, Germany. thorsten.bley@uniklinik-freiburg.de
authors.forename: Thorsten Alexander
authors.initials: TA
authors.lastname: Bley
authors.forename: Tobias
authors.initials: T
authors.lastname: Baumann
authors.forename: Ulrich
authors.initials: U
authors.lastname: Saueressig
authors.forename: Gregor
authors.initials: G
authors.lastname: Pache
authors.forename: Markus
authors.initials: M
authors.lastname: Treier
authors.forename: Oliver
authors.initials: O
authors.lastname: Schaefer
authors.forename: Ulrich
authors.initials: U
authors.lastname: Neitzel
authors.forename: Mathias
authors.initials: M
authors.lastname: Langer
authors.forename: Elmar
authors.initials: E
authors.lastname: Kotter
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D002983:Clinical Competence; D003936:Diagnosis, Computer-Assisted; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011856:Radiographic Image Enhancement / Q000379:methods*; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D003074:Solitary Pulmonary Nodule / Q000000981:diagnostic imaging*; D018709:Statistics, Nonparametric; D014057:Tomography, X-Ray Computed