Acute respiratory distress syndrome (ARDS) is a clinical condition first described by Ashbaugh et al in 1967 using the term ?adult respiratory distress syndrome?1. In order to establish a diagnosis of ARDS, radiological findings are necessary and they serve as one of the postulates. According to the latest definition, which was created by a panel of experts in 2011 in Berlin, thus termed the Berlin definition of ARDS, ARDS2 is a condition starting within 1 week of clinical insult with bilateral infiltrates detectable by chest imaging (either conventional radiography or multidetector computed tomography (MDCT) scan of lungs) and severe hypoxemia in the absence of evidence for cardiogenic pulmonary edema or fluid overload. It is necessary to explain the origin of edema, and to do that we need objective assessment (e.g., echocardiography) in order to exclude cardiogenic factors. Severity of ARDS is based on ratio between partial oxygen pressure in arterial blood and fraction of oxygen in the inspired air (PaO2 /FIO2) on 5 cm of continuous positive airway pressure (CPAP). The 3 categories are mild (PaO2/FIO2 200-300), moderate (PaO2/FIO2 100-200) and severe (PaO2/FIO2 =100). The definition itself says that in order to make a diagnosis we must do radiology imaging, although it does not say which one should be performed, the conventional radiography or MDCT. ARDS represents a stereotypic response to many different inciting insults and goes through a number of different phases, from alveolar capillary damage to lung resolution or a fibro-proliferative and fibrotic phase. The pulmonary epithelial and endothelial cellular damage is characterized by inflammation, apoptosis, necrosis and increased alveolar capillary permeability, which lead to development of alveolar edema. Purpose and role of radiographic methods is to assist in the visualization of above mentioned pathomorphological substrate. Because of the fact that sensitivity of conventional radiography is significantly lower than that of MDCT imaging, MDCT could be the primary method of choice in the initial diagnosis, but for the patient with ARDS it is most important that he has the best conditions concerning mechanical ventilation, which is very complicated to provide during the transportation of the patient from intensive care unit to MDCT diagnostic unit. As the disease evolves inside the lung area, some of the complications can be visualized only with MDCT. That is one of the main reasons MDCT is used for that period of disease evolution. Because of everything that is mentioned above, it is hard to decide whether and when MDCT scan should be performed.