title: Organizing pneumonia: prognostic implication of high-resolution computed tomography features.
abstract: OBJECTIVE
  Most patients with biopsy-proven organizing pneumonia (OP) show complete resolution of radiographic lesions with treatment, but some patients do not respond to treatment and progress to pulmonary fibrosis. The authors investigated the prognostic implication of high-resolution computed tomography (CT) features in this condition.
  
  
  METHODS
  We reviewed the high-resolution CT findings of 26 patients diagnosed with OP by histopathology, who had radiographic follow-up for a median of 44 weeks after treatment. We scored the presence and extent of each pretreatment high-resolution CT finding (ground-glass opacity, consolidation, nodules, reticular opacity, and honeycombing). The predominant pattern and distribution of the lesions were recorded. Follow-up radiographs were used to determine whether the parenchymal abnormalities had regressed or progressed in response to treatment.
  
  
  RESULTS
  Of the 26 patients, 9 had persistent or progressive parenchymal abnormalities at follow-up (group 1), whereas 17 had complete or partial resolution of abnormalities (group 2). Consolidation was present on the initial CT scan in 14 (82%) of the 17 patients in group 2, but in only 2 of the 9 patients in group 1 (P = 0.009). None of the 6 patients who had reticular abnormality as the predominant pattern on initial CT showed complete resolution on follow-up imaging (P = 0.02).
  
  
  CONCLUSIONS
  In patients with OP, the CT finding of consolidation is associated with partial or complete resolution, whereas reticular opacity is associated with persistent or progressive disease.
authors.affiliation: Department of Radiology, Health Sciences Center, University of Colorado School of Medicine, Denver, CO 80262, USA.
authors.forename: Jin Seong
authors.initials: JS
authors.lastname: Lee
authors.forename: David A
authors.initials: DA
authors.lastname: Lynch
authors.forename: Surit
authors.initials: S
authors.lastname: Sharma
authors.forename: Kevin K
authors.initials: KK
authors.lastname: Brown
authors.forename: Nestor L
authors.initials: NL
authors.lastname: Müller
mesh_terms: D000368:Aged; D018450:Disease Progression; D005260:Female; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging / Q000473:pathology; D008297:Male; D015588:Observer Variation; D011014:Pneumonia / Q000175:diagnosis* / Q000453:epidemiology; D015995:Prevalence; D011379:Prognosis; D013902:Radiography, Thoracic; D012008:Recurrence; D013997:Time Factors; D014057:Tomography, X-Ray Computed