title: [Chest high resolution CT features of extrinsic allergic alveolitis and its diagnostic value].
abstract: OBJECTIVE
  To summarize the chest high-resolution CT (HRCT) features of the patients with extrinsic allergic alveolitis (EAA).
  
  
  METHODS
  We analyzed the images of chest HRCT of 34 patients diagnosed as EAA at our hospital from February 2001 to August 2009.
  
  
  RESULTS
  All patients had a history of environmental exposure. The duration of intermittent or continuous antigen exposure was from 3 months to 13 years. Two patients showed acute clinical manifestations. There were 22 sub-acute and 10 chronic cases. Acute EAA was characterized by ground-glass opacities, air trapping and/or mosaic sign on HRCT. The HRCT features of subacute EAA included patchy ground-glass opacities with mosaic sign (n = 11, 50.0%) and diffusely distributed centrilobular nodules (n = 7, 31.8%) with mosaic sign (n = 4, 18.2%). All patients with chronic EAA had reticular and honeycombing lesions on HRCT. There were 3 cases with ground-glass opacities, 3 with mosaic sign, and 3 with centrilobular nodules.
  
  
  CONCLUSIONS
  The typical findings of chest HRCT are helpful for making a diagnosis and differential diagnosis of EAA.
authors.affiliation: Department of Respiratory and Critical Care Medicine, Beijing Institute of Respiratory Medicine, Beijing Chaoyang Hospital Affiliated to Capital Medical University, Beijing 100020, China.
authors.forename: Cheng-jun
authors.initials: CJ
authors.lastname: Ban
authors.forename: Hua-ping
authors.initials: HP
authors.lastname: Dai
authors.forename: Shu
authors.initials: S
authors.lastname: Zhang
authors.forename: Lei
authors.initials: L
authors.lastname: Zhang
authors.forename: Qiao
authors.initials: Q
authors.lastname: Ye
authors.forename: Min
authors.initials: M
authors.lastname: Zhu
mesh_terms: D000328:Adult; D000368:Aged; D000542:Alveolitis, Extrinsic Allergic / Q000000981:diagnostic imaging* / Q000473:pathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D013902:Radiography, Thoracic; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D055815:Young Adult