Lung function parameters have been used in most therapeutic studies to date. Thanks to improvements in cystic fibrosis (CF) therapy, these parameters have become a less sensitive endpoint in clinical studies. Computed tomography (CT) in CF can identify highly relevant structural lung changes, such as bronchiectasis and air trapping. CT scoring systems have been developed to quantify in a systematic fashion these structural changes on CT scans. Clinical studies have been conducted using CT scores as an outcome parameter. These studies suggest strongly that CT scoring is more sensitive than pulmonary function tests for the detection of relevant disease progression in CF. Bronchiectasis, which is progressive and irreversible in CF, is probably the most relevant structural change on CT scans that can be scored reliably. CT measurement of airway wall thickening is possible. Airway wall thickening is related to inflammation; thus, this endpoint is of significance for interventional studies that include antiinflammatory drugs.