Validation of a Semi-automatized Method to Detect Cyclic Hyperinflation on CT-scan in ARDS

Inclusion Criteria: * ARDS patients defined by the Berlin definition * invasive mechanical ventilation with an arterial oxygen pressure (PaO2)/inspired fraction of oxygen (FiO2) ratio ≤ 200 mm Hg * Indication of CT scan identified by the clinician in charge * oesophageal catheter already inserted Exclusion Criteria: * requirement of contrast agent for a chest CT-scan * ARDS criteria present for more than 72 hours * Chronic Obstructive Pulmonary Disease (COPD) on a previous lung function test * pneumothorax or bronchopleural fistula * patient without both sedation and neuromuscular blocking agents * contra-indication to transport to the imaging facility * treatment with extracorporeal membrane oxygenation or extracorporeal carbon dioxide (CO2) removal * Latex or curare allergy * patient previously included in the study * pregnancy * patient under limitation of care * patient under an exclusion period following inclusion in another clinical trial * patient under a legal protective measure * patient unaffiliated with social security * inform consent not obtained by next of kin