title: Interobserver agreement for the ATS/ERS/JRS/ALAT criteria for a UIP pattern on CT.
abstract: OBJECTIVE
  To establish the level of observer variation for the current ATS/ERS/JRS/ALAT criteria for a diagnosis of usual interstitial pneumonia (UIP) on CT among a large group of thoracic radiologists of varying levels of experience.
  
  
  METHODS
  112 observers (96 of whom were thoracic radiologists) categorised CTs of 150 consecutive patients with fibrotic lung disease using the ATS/ERS/JRS/ALAT CT criteria for a UIP pattern (3 categories--UIP, possibly UIP and inconsistent with UIP). The presence of honeycombing, traction bronchiectasis and emphysema was also scored using a 3-point scale (definitely present, possibly present, absent). Observer agreement for the UIP categorisation and for the 3 CT patterns in the entire observer group and in subgroups stratified by observer experience, were evaluated.
  
  
  RESULTS
  Interobserver agreement across the diagnosis category scores among the 112 observers was moderate, ranging from 0.48 (IQR 0.18) for general radiologists to 0.52 (IQR 0.20) for thoracic radiologists of 10-20 years' experience. A binary score for UIP versus possible or inconsistent with UIP was examined. Observer agreement for this binary score was only moderate. No significant differences in agreement levels were identified when the CTs were stratified according to multidisciplinary team (MDT) diagnosis or patient age or when observers were categorised according to experience. Observer agreement for each of honeycombing, traction bronchiectasis and emphysema were 0.59±0.12, 0.42±0.15 and 0.43±0.18, respectively.
  
  
  CONCLUSIONS
  Interobserver agreement for the current ATS/ERS/JRS/ALAT CT criteria for UIP is only moderate among thoracic radiologists, irrespective of their experience, and did not vary with patient age or the MDT diagnosis.
authors.affiliation: Department of Radiology, Kings College Hospital Foundation Trust, London, UK.
authors.forename: Simon L F
authors.initials: SL
authors.lastname: Walsh
authors.affiliation: Department of Bioimaging and Radiological Sciences, Institute of Radiology, Catholic University, "A. Gemelli" Hospital, Rome, Italy.
authors.forename: Lucio
authors.initials: L
authors.lastname: Calandriello
authors.affiliation: Department of Clinical Sciences, Section of Radiology, University of Parma, Parma, Italy.
authors.forename: Nicola
authors.initials: N
authors.lastname: Sverzellati
authors.affiliation: Interstitial Lung Diseases Unit, Royal Brompton Hospital, London, UK.
authors.forename: Athol U
authors.initials: AU
authors.lastname: Wells
authors.affiliation: Department of Radiology, Royal Brompton Hospital, London, UK.
authors.forename: David M
authors.initials: DM
authors.lastname: Hansell
mesh_terms: D002983:Clinical Competence; D018450:Disease Progression; D005260:Female; D006801:Humans; D054988:Idiopathic Interstitial Pneumonias / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D010818:Practice Patterns, Physicians'; D011379:Prognosis; D013902:Radiography, Thoracic / Q000592:standards*; D014057:Tomography, X-Ray Computed / Q000592:standards*
keywords: Idiopathic pulmonary fibrosis; Imaging/CT MRI etc; Interstitial Fibrosis