Feldhaus FW, et al. - In chronic obstructive pulmonary disease (COPD) patients with Global Initiative for Chronic Obstructive Lung Disease (GOLD) stages III or IV and pulmonary emphysema studied in this retrospective analysis, researchers investigated whether the lung function was measurably affected by high attenuation areas as a correlate of concomitant unspecific fibrotic changes of lung parenchyma. CT and pulmonary function tests were performed on 88 patients with COPD GOLD stage III or IV. Findings revealed no significant correlation of high attenuation volume (HAV), unlike low attenuation volume (LAV), with parameters of lung function. A significant negative correlation with forced expiratory volume in 1 second was demonstrated only by LAV even in patients with a comparatively high HAV of more than 10%, in contrast to HAV. Emphysematous changes of lung parenchyma appeared to have such a strong impact on lung function among the participants, which is a likely influence of concomitant unspecific fibrosis is overwhelmed.