Crazy-paving appearance at thin-section CT: spectrum of disease and pathologic findings

Radiology. 1999 Apr;211(1):155-60. doi: 10.1148/radiology.211.1.r99ap10155.


Purpose: To determine the spectrum of disease associated with a fine reticular pattern superimposed on areas of ground-glass opacity (i.e., "crazy-paving" appearance) at thin-section computed tomography (CT) and to determine the underlying pathologic features.

Materials and methods: In the in vivo study, the cases of 46 patients (21 male, 25 female; age range, 13-82 years) were retrospectively reviewed, with special attention paid to the size and extent of the reticular network. In the in vitro study, the thin-section CT findings in 20 inflated and fixed lungs were precisely correlated with the gross appearance, contact radiograph findings, stereomicroscopic views, and histologic findings.

Results: In the in vivo study, 15 different diseases were identified, including alveolar proteinosis, adult respiratory distress syndrome, acute interstitial pneumonia, diffuse alveolar damage superimposed on usual interstitial pneumonia, and drug-induced pneumonitis. In the in vitro study, the fine networks at pathologic analysis were due to an alveolar filling process (n = 10), an interstitial fibrotic process (n = 7), or a combination of interstitial and intraalveolar processes (n = 3). Twelve (60%) cases did not have thickening of the interlobular septa within the areas of the crazy-paving appearance.

Conclusion: The crazy-paving appearance is a nonspecific finding seen in a variety of interstitial and airspace lung diseases.

MeSH terms

  • Female
  • Humans
  • Lung / diagnostic imaging
  • Lung / pathology
  • Lung Diseases / diagnostic imaging*
  • Lung Diseases / pathology
  • Lung Diseases, Interstitial / diagnostic imaging
  • Lung Diseases, Interstitial / pathology
  • Male
  • Middle Aged
  • Tomography, X-Ray Computed / methods*