Computed tomography scanning in ARDS

The conventional chest X-ray has remained until now the most frequently used radiological tool for patients with lung disease in the intensive care unit (ICU). Since the first studies carried out with thoracic computed tomography (CT) in patients with acute lung injury (ALI) or acute respiratory distress syndrome (ARDS) around 1980, the CT scan has become an invaluable tool in the management of patients with respiratory failure. The CT scan can provide useful information not seen on the conventional chest X-ray, such as a localised anterior pneumothorax or lung abscess; moreover the image is free of any superimposition of the different anatomical structures. We reviewed 70 ARDS patients examined with a CT scan, and we found that in 30% of the cases the CT scan offered new information leading to changes in therapeutic management. However, a CT scan necessitates the patient being moved from the ICU, is costly and exposes the patient to a greater amount of radiation than the conventional chest X-ray. In this article we will present the basic principles of the CT scan as well the major insights into the pathophysiology of ALI/ARDS obtained by this technique.