title: Asbestos-related disease: progression of parenchymal abnormalities on high-resolution CT.
abstract: OBJECTIVE
  To evaluate the changes over time in the pattern and extent of parenchymal abnormalities in asbestos-exposed workers after cessation of exposure and to compare 3 proposed semiquantitative methods with a careful side-by-side comparison of the initial and the follow-up computed tomography (CT) images.
  
  
  METHODS
  The study included 52 male asbestos workers (mean age+/-SD, 62.2 y+/-8.2) who had baseline high-resolution CT after cessation of exposure and follow-up CT 3 to 5 years later. Two independent thoracic radiologists quantified the findings according to the scoring systems proposed by Huuskonen, Gamsu, and Sette and then did a side-by-side comparison of the 2 sets of scans without awareness of the dates of the CT scans.
  
  
  RESULTS
  There was no difference in the prevalence of the 2 most common parenchymal abnormalities (centrilobular small dotlike or branching opacities and interstitial lines) between the initial and follow-up CT scans. Honeycombing (20%) and traction bronchiectasis and bronchiolectasis (50%) were seen more commonly on the follow-up CT than on the initial examination (10% and 33%, respectively) (P=0.01). Increased extent of parenchymal abnormalities was evident on side-by-side comparison in 42 (81%) patients but resulted in an increase in score in at least 1 semiquantitative system in only 16 (31%) patients (all P>0.01, signed test).
  
  
  CONCLUSIONS
  The majority of patients with previous asbestos exposure show evidence of progression of disease on CT at 3 to 5 years follow-up but this progression is usually not detected by the 3 proposed semiquantitative scoring schemes.
authors.affiliation: Department of Radiology, Vancouver General Hospital, The University of British Columbia, Vancouver, BC, Canada. isabela.silva@vch.ca
authors.forename: C Isabela S
authors.initials: CI
authors.lastname: Silva
authors.forename: Nestor L
authors.initials: NL
authors.lastname: Müller
authors.forename: J Alberto
authors.initials: JA
authors.lastname: Neder
authors.forename: Cristiano Rabelo
authors.initials: CR
authors.lastname: Nogueira
authors.forename: Lara Maris
authors.initials: LM
authors.lastname: Nápolis
authors.forename: Mário
authors.initials: M
authors.lastname: Terra-Filho
authors.forename: Ericson
authors.initials: E
authors.lastname: Bagatin
authors.forename: Luiz E
authors.initials: LE
authors.lastname: Nery
mesh_terms: D000328:Adult; D000368:Aged; D001195:Asbestosis / Q000000981:diagnostic imaging*; D018450:Disease Progression; D006801:Humans; D008297:Male; D008875:Middle Aged; D009784:Occupational Diseases / Q000000981:diagnostic imaging*; D016273:Occupational Exposure / Q000009:adverse effects*; D011857:Radiographic Image Interpretation, Computer-Assisted; D014057:Tomography, X-Ray Computed / Q000379:methods*