Crazy-paving Appearance at Thin-Section CT: Spectrum of Disease and Pathologic Findings

PURPOSE: To determine the spectrum of diseases associated with a fine reticular pattern superimposed on areas of ground-glass opacity (ie, “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.


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Article History

Published in print: Apr 1999