Crazy-Paving Pattern

Fig. Axial CT of the chest shows diffuse bilateral ground-glass opacities superimposed by interlobular septal thickening (arrowheads) and intralobular lines (blue arrows). Note a left chest tube used to treat left pneumothorax, which brought this patient to the hospital.

What is "Crazy-Paving" Pattern?

• Ground-glass opacity superimposed with interlobular septal thickening and intralobular lines
  
• Can be scattered or diffuse
  
• Can be caused by alveolar filling process, interstitial process, or a combination

What Can Cause "Crazy-Paving" Pattern?

• CLASSIC: Pulmonary alveolar proteinosis 
  
• COMMON: Pneumocystis jirovecii pneumonia (PCP), pulmonary edema (ARDS), pulmonary hemorrhage
  
• NOT COMMON: Bronchioloalveolar carcinoma, alveolar sarcoidosis, nonspecific interstitial pneumonitis (NSIP), Cryptogenic organizing pneumonia (COP), lipoid pneumonia
  

Our case is a patient with biopsy proven pulmonary alveolar proteinosis.

Reference:

1. Rossi SE, et al. "Crazy-Paving" Pattern at Thin-Section CT of the Lungs: Radiologic-Pathologic Overview. Radiographics 2003;23:1509.

2. Johkoh T, et al. Crazy-paving Appearance at Thin-Section CT: Spectrum of Disease and Pathologic Findings. Radiology 1999;211:155.