The natural course of COPD is associated with episodes of exacerbation which are clinically defined as acute events characterized by a worsening of the patient's respiratory symptoms that is beyond normal day-to-day variations and which leads to a change in medication. Moreover, these episodes can be classified into mild, moderate, or severe exacerbations, following patient's need for medical environment. While the cause of about one-third of severe exacerbation episodes cannot be identified, two-thirds are associated with certain conditions such as respiratory tract infections (viral or bacterial), air pollution, as well as pulmonary embolism (PE), pulmonary edema, cardiac arrhythmia, pneumothorax, or pleural effusion. As COPD exacerbations are associated with increased morbidity and mortality, as well as with increased healthcare costs, their prevention and treatment are two major objectives in COPD management with subsequent requirement for appropriate assessment tools. As imaging tool, chest radiography is limited to the detection of pneumonia and pleural abnormalities, and only leads to change in managements in a marginal proportion of patients. However, while Computed Tomography (CT) scans allows detecting more chest abnormalities, the knowledge of CT features at the time of exacerbation is a pre-requisite for determining possible role of CT in routine work-up of exacerbation. Nevertheless these features remain widely unknown, previous studies having focused on the prevalence of PE. The aim of our study was therefore to describe these features by comparing CT scans performed at severe exacerbation with control scans.
