title: Nonspecific interstitial pneumonia and usual interstitial pneumonia: comparative appearances at and diagnostic accuracy of thin-section CT.
abstract: OBJECTIVE
  To compare the morphologic abnormalities on thin-section computed tomographic (CT) images in a group of patients with histopathologically confirmed nonspecific interstitial pneumonia (NSIP) or usual interstitial pneumonia (UIP) and a clinical presentation of idiopathic pulmonary fibrosis.
  
  
  METHODS
  Thin-section CT imaging patterns and distribution of disease in 53 patients with histologic diagnoses of NSIP (n = 21) or UIP (n = 32) were quantified retrospectively and independently by four observers. The appearances of NSIP and UIP at CT were compared with univariate and multivariate techniques.
  
  
  RESULTS
  The use of thin-section CT proved to have moderate sensitivity (70%), specificity (63%), and accuracy (66%) in the diagnosis of NSIP. An increased proportion of ground-glass attenuation was the cardinal feature of NSIP at CT (odds ratio: 1.04 for each 1% increase in the proportion of ground-glass attenuation). A histologic diagnosis of NSIP was most frequent (in 24 of 35 observations [69%]) when ground-glass attenuation predominated, and was more frequent with mixed (35 of 79 observations [44%]) than with predominantly reticular disease (25 of 98 [26%] observations, P < .005). Logistic regression analysis of the data indicated that misdiagnosis of UIP in patients with NSIP was associated with less ground-glass attenuation (P < .005) at CT and a subpleural disease distribution (P = .02), with the converse being true for UIP cases misdiagnosed as NSIP.
  
  
  CONCLUSIONS
  In patients with a clinical presentation of idiopathic pulmonary fibrosis, the accuracy of thin-section CT in identifying NSIP is considerably higher than previously reported. At CT, NSIP is characterized by more ground-glass attenuation and a finer reticular pattern than is UIP. Nevertheless, considerable overlap in thin-section CT patterns exists between NSIP and UIP.
authors.affiliation: Department of Radiology, Royal Brompton Hospital, Sydney St, London SW3 6NP, England.
authors.forename: S L
authors.initials: SL
authors.lastname: MacDonald
authors.forename: M B
authors.initials: MB
authors.lastname: Rubens
authors.forename: D M
authors.initials: DM
authors.lastname: Hansell
authors.forename: S J
authors.initials: SJ
authors.lastname: Copley
authors.forename: S R
authors.initials: SR
authors.lastname: Desai
authors.forename: R M
authors.initials: RM
authors.lastname: du Bois
authors.forename: A G
authors.initials: AG
authors.lastname: Nicholson
authors.forename: T V
authors.initials: TV
authors.lastname: Colby
authors.forename: A U
authors.initials: AU
authors.lastname: Wells
mesh_terms: D001706:Biopsy; D003951:Diagnostic Errors; D005260:Female; D006801:Humans; D016015:Logistic Models; D008168:Lung / Q000000981:diagnostic imaging / Q000473:pathology; D017563:Lung Diseases, Interstitial / Q000145:classification / Q000000981:diagnostic imaging* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D011658:Pulmonary Fibrosis / Q000000981:diagnostic imaging / Q000473:pathology; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed