Chronic hypersensitivity pneumonitis: use of CT in diagnosis

AJR Am J Roentgenol. 1992 Nov;159(5):957-60. doi: 10.2214/ajr.159.5.1414806.


Objective: In its subacute or chronic form, hypersensitivity pneumonitis is often difficult to distinguish clinically and physiologically from other idiopathic diffuse lung diseases. The aim of this study was to identify high-resolution CT features that allow distinction of chronic hypersensitivity pneumonitis from other chronic diffuse parenchymal lung diseases.

Materials and methods: Six patients with chronic hypersensitivity pneumonitis were examined with pulmonary function testing, bronchoalveolar lavage, lung biopsy, chest radiography, and high-resolution CT. The chest radiographs and high-resolution CT scans were reviewed independently by three observers without knowledge of the patients' clinical status. Discrepancies between the observers were resolved by consensus.

Results: The chest radiographs revealed normal lung volumes with a combination of abnormalities: a mixed alveolar/interstitial pattern in five cases, peribronchiolar thickening in three, a diffuse granular pattern in one, and a linear fibrotic pattern in one. In general, the high-resolution CT scans showed more abnormalities than were apparent on the plain chest radiographs. High-resolution CT revealed centrilobular, peribronchiolar, indistinct nodular opacities, of various numbers, in all cases. Four cases had areas of ground-glass density, three cases had lobular areas of hyperlucency, and one case had areas of pulmonary fibrosis and honeycombing.

Conclusion: We confirm that high-resolution CT can most clearly show the type and distribution of parenchymal abnormalities in patients with hypersensitivity pneumonitis. Importantly, although not pathognomonic, the high-resolution CT finding of centrilobular, peribronchiolar, indistinct nodules should suggest the diagnosis of chronic hypersensitivity pneumonitis.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Alveolitis, Extrinsic Allergic / diagnosis
  • Alveolitis, Extrinsic Allergic / diagnostic imaging*
  • Biopsy
  • Bronchoalveolar Lavage Fluid / pathology
  • Chronic Disease
  • Female
  • Humans
  • Lung / diagnostic imaging
  • Lung / pathology
  • Male
  • Middle Aged
  • Respiratory Function Tests
  • Tomography, X-Ray Computed / methods