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 pathologi...