title: Comparison of digital with film radiographs for the classification of pneumoconiotic pleural abnormalities.
abstract: OBJECTIVE
  Analog film radiographs are typically used to classify pneumoconiosis to allow comparison with standard film radiographs. The aim of this study was to determine if digital radiography is comparable to film for the purpose of classifying pneumoconiotic pleural abnormalities.
  
  
  METHODS
  Subjects were 200 asbestos-exposed patients, from whom digital and film chest radiographs were obtained along with chest high-resolution computed tomographic scans. Using a crossover design, radiographs were independently read on two occasions by seven readers, using conventional International Labour Organization standards for film and digitized standards for digital. High-resolution computed tomographic scans were read independently by three readers. Areas under the receiver-operating characteristic curves were calculated using high-resolution computed tomographic ratings as the gold standard for disease status. Mixed linear models were fit to estimate the effects of order of presentation, occasion, and modality, treating the seven readers as a random effect. Comparing digital and film radiography for each reader and occasion, crude agreement and agreement beyond chance (κ) were also calculated.
  
  
  RESULTS
  The linear models showed no statistically significant sequence effect for order of presentation (P = .73) or occasion (P = .28). Most important, the difference between modalities was not statistically significant (digital vs film, P = .54). The mean area under the curve for film was 0.736 and increased slightly to 0.741 for digital. Mean crude agreement for the presence of pleural abnormalities consistent with pneumoconiosis across all readers and occasions was 78.3%, while the mean κ value was 0.49.
  
  
  CONCLUSIONS
  These results indicate that digital radiography is not statistically different from analog film for the purpose of classifying pneumoconiotic pleural abnormalities, when appropriate standards are used.
authors.affiliation: Division of Health Studies, Agency for Toxic Substances and Disease Registry, Atlanta, GA 30341, USA. tlarson@cdc.gov
authors.forename: Theodore C
authors.initials: TC
authors.lastname: Larson
authors.forename: David B
authors.initials: DB
authors.lastname: Holiday
authors.forename: Vinicius C
authors.initials: VC
authors.lastname: Antao
authors.forename: Jerry
authors.initials: J
authors.lastname: Thomas
authors.forename: Germania
authors.initials: G
authors.lastname: Pinheiro
authors.forename: Vikas
authors.initials: V
authors.lastname: Kapil
authors.forename: Alfred
authors.initials: A
authors.lastname: Franzblau
mesh_terms: D019540:Area Under Curve; D018592:Cross-Over Studies; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D010995:Pleural Diseases / Q000000981:diagnostic imaging*; D011009:Pneumoconiosis / Q000145:classification* / Q000000981:diagnostic imaging*; D012372:ROC Curve; D011856:Radiographic Image Enhancement / Q000379:methods*; D013902:Radiography, Thoracic / Q000145:classification* / Q000379:methods*; D015203:Reproducibility of Results; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014962:X-Ray Film