Pathogenesis, Imaging, and Evolution of Acute Lung Injury

Acute lung injury (ALI) exists on a continuum that includes diffuse alveolar damage, acute fibrinous and organizing pneumonia, and organizing pneumonia. The primary site of injury in ALI is the same, which likely explains similar imaging patterns across the pathologic spectrum. Radiologic outcomes in ALI depend on the degree of injury and the subsequent healing response. Although ALI can heal without permanent injury, development of fibrosis is not uncommon and may be debilitating. ALI is associated with the usual interstitial pneumonia and nonspecific interstitial pneumonia patterns of fibrosis and repeated episodes of ALI are likely a cause of fibrosis progression.