In this multicenter study the comparison of the mass flow distribution and redistribution
versus the relative blood flow per lobe (as a surrogate for Ventilation/ Perfusion (V/Q)
matching) with functional respiratory imaging (FRI) and arterial blood gas (ABG) values will
be evaluated in hypercapnic Chronic Obstructive Pulmonary Disease (COPD) patients. Therefore
a low dose Computed Tomography (CT) scan will be taken in a population of 30 patients with
non-invasive ventilation (NIV) and in a control group of 10 patients without NIV. The CT-scan
will be used for FRI.