title: Nonspecific interstitial pneumonia and idiopathic pulmonary fibrosis: changes in pattern and distribution of disease over time.
abstract: OBJECTIVE
  To retrospectively assess the change in disease pattern of nonspecific interstitial pneumonia (NSIP) and idiopathic pulmonary fibrosis (IPF) findings seen at thin-section computed tomography (CT) at long-term follow-up and to compare the same with initial findings at CT.
  
  
  METHODS
  The study included 48 patients (28 men, 20 women; mean age, 57.5 years) with biopsy-proved NSIP (n = 23) or IPF (n = 25) who underwent CT at initial diagnosis and at follow-up 34-155 months later. The CT scans were randomized and reviewed by two independent thoracic radiologists for pattern and distribution of ground-glass opacity (GGO), reticulation, traction bronchiectasis and bronchiolectasis, and honeycombing. Statistical analysis was performed by using nonparametric methods and univariate logistic regression.
  
  
  RESULTS
  Follow-up CT in patients with NSIP showed marked decrease in the extent of GGO, increase in reticulation, and a greater likelihood of peripheral distribution (all P < .05). At presentation, the CT findings were interpreted as suggestive of NSIP in 18 of 23 patients with NSIP and indeterminate or suggestive of IPF in five. In five (28%) of 18 patients with initial findings suggestive of NSIP, the follow-up CT scans were interpreted as more suggestive of IPF. No CT features seen at presentation allowed distinction between patients with NSIP that maintained an NSIP pattern at follow-up and those that progressed to an IPF pattern.
  
  
  CONCLUSIONS
  At follow-up CT, 28% of patients with initial CT findings suggestive of NSIP progressed to findings suggestive of IPF. Similar initial CT findings for NSIP may have different imaging outcomes.
authors.affiliation: Department of Radiology, Vancouver General Hospital, University of British Columbia, 3350-950 W 10th Ave, Vancouver, BC, Canada V5Z 4E3. 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: David M
authors.initials: DM
authors.lastname: Hansell
authors.forename: Kyung S
authors.initials: KS
authors.lastname: Lee
authors.forename: Andrew G
authors.initials: AG
authors.lastname: Nicholson
authors.forename: Athol U
authors.initials: AU
authors.lastname: Wells
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging*; D017563:Lung Diseases, Interstitial / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D011658:Pulmonary Fibrosis / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed