The bedside chest radiograph represents the imaging modality of choice for diagnosis and monitoring of adult respiratory distress syndrome (ARDS). Imaging findings are strongly influenced by means of mechanical ventilation therapy. The chest radiograph is relatively insensitive and not specific for the diagnosis of complications such as pneumonia or interstitial emphysema. Computed tomography (CT) is suitable for quantitative assessment of lung compartments with respect to the degree of aeration and to tissue density values. With CT, the understanding of the underlying pathophysiology and the effects of ventilation therapy (PEEP) could be improved. The role of CT in the clinical routine is still limited due to the high risk to transport patients with ARDS.