This prospective trial aims to phenotype COPD by using Imaging methods.The identification of different COPD phenotypes, such as the "emphysema-type" and the "airway-type", is important because therapy and prognosis will be different. Imaging might play a central role in diagnosing these phenotypes. So far computed tomography (CT) is regarded as the gold standard, but it involves ionizing radiation and lacks functional information. The medical problem addressed in this trial is the image-based phenotyping of COPD. The principal research question is whether magnetic resonance imaging (MRI) can replace CT for the characterization of COPD by "structural and functional phenotyping" on a regional basis. The sensitivity and specificity of MRI will be compared to CT serving as the gold standard. To achieve this goal, MRI and CT of the lung will be performed in a multi-centre cohort of 625 COPD-patients from the main Cosyconet cohort. Also, the reliability of the MRI results will be demonstrated. MRI phenotypes will be evaluated visually and using software with quantitative read-outs. The agreement of both will be determined. The additional information of MRI over CT will be assessed. A special focus will be to implement an image-based biomarker of pulmonary functional reserve derived from the MRI measurement of pulmonary perfusion, which will be correlated with results from pulmonary functions tests (e.g. the lung transfer factor for carbon monoxide (TLCO)) the 6-minute walking test (6-MWD), and extrapulmonary disease manifestations.
