Biopsy-proved idiopathic pulmonary fibrosis: spectrum of nondiagnostic thin-section CT diagnoses

Radiology. 2010 Mar;254(3):957-64. doi: 10.1148/radiol.0990898.


Purpose: To document the spectrum of misleading thin-section computed tomographic (CT) diagnoses in patients with biopsy-proved idiopathic pulmonary fibrosis (IPF).

Materials and methods: This study had institutional review board approval, and patient consent was not required. Three observers, blinded to any clinical information and the purpose of the study, recorded thin-section CT differential diagnoses and assigned a percentage likelihood to each for a group of 123 patients (79 men, 44 women; age range, 27-82 years) with various chronic interstitial lung diseases, including a core group of 55 biopsy-proved cases of IPF. Patients with IPF in the core group, in whom IPF was diagnosed as low-grade probability (<30%) by at least two observers, were considered to have atypical IPF cases, and the alternative diagnoses were analyzed further.

Results: Thirty-four (62%) of 55 biopsy-proved IPF cases were regarded as alternative diagnoses. In these atypical IPF cases, the first-choice diagnoses, expressed with high degree of probability, were nonspecific interstitial pneumonia (NSIP; 18 [53%] of 34), chronic hypersensitivity pneumonitis (HP; four [12%] of 34), sarcoidosis (three [9%] of 34), and organizing pneumonia (one [3%] of 34); in eight (23%) of 34 cases, no single diagnosis was favored by more than one observer. Frequent differential diagnoses, although not always the first-choice diagnosis, were NSIP (n = 29), chronic HP (n = 23), and sarcoidosis (n = 9).

Conclusion: In the correct clinical setting, a diagnosis of IPF is not excluded by thin-section CT appearances more suggestive of NSIP, chronic HP, or sarcoidosis. (c) RSNA, 2010.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Alveolitis, Extrinsic Allergic / diagnostic imaging
  • Biopsy
  • Diagnosis, Differential
  • Female
  • Humans
  • Idiopathic Pulmonary Fibrosis / diagnostic imaging*
  • Idiopathic Pulmonary Fibrosis / pathology
  • Lung Diseases, Interstitial / diagnostic imaging
  • Male
  • Middle Aged
  • Proportional Hazards Models
  • Retrospective Studies
  • Sarcoidosis, Pulmonary / diagnostic imaging
  • Tomography, X-Ray Computed / methods*