Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The cardiac silhouette size is mildly enlarged . Mediastinal contours are unchanged , with mild tortuosity of the thoracic aorta again noted . There are atherosclerotic calcifications at the aortic knob . The pulmonary vasculature is not engorged . Streaky opacities in the lung bases likely reflect atelectasis . No focal consolidation , pleural effusion or pneumothorax is demonstrated . There are multilevel degenerative changes in the thoracic spine .
    OUTPUT:
    
Mild bibasilar patchy opacities likely reflect atelectasis , but infection is not excluded in the correct clinical setting .