• Etiology: transient collection of interstitial air due to staphlococcus pneumonia (necrotic bronchi), chest trauma, positive pressure ventilation, hydrocarbon ingestion
  • Imaging: has thin wall, usually no air-fluid level, occurs later in infection
  • DDX: abscess
    — Abscess appears earlier in infection, has thick irregular walls, lasts long time
    — Pneumatocoele occurs later in infection, has thin wall, usually no air fluid level

Cases of Pneumatocele

CXR of pneumatocele
CXR shows a large thin walled cystic lesion in the left lower lobe.