Alveolar edema

Pulmonary alveolar edema is a particular pattern of pulmonary edema where most of the fluid build up is in the alveolar spaces. The onset of alveolar edema may also be associated with direct pressure-induced damage to the alveolar epithelium. It can sometimes have a central perihilar pattern. Alveolar pulmonary edema is often preceded by interstitial pulmonary edema and usually develops once the pulmonary venous pressure exceeds 30 mmHg .

Radiographic features

Plain radiograph

On chest radiographs, there are often bilateral opacities that extend in a fan-shape outwards from the hilum in a ‘batwing’ pattern. With worsening alveolar edema, the lung opacification can become increasingly homogenous. Air bronchograms may be seen with alveolar edema .