Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Mild enlargement of cardiac silhouette is unchanged . The aortic knob is calcified . The mediastinal and hilar contours are similar . Pulmonary vasculature is normal . Streaky bibasilar airspace opacities likely reflect atelectasis . No focal consolidation , pleural effusion or pneumothorax is present . No acute osseous abnormalities identified .
    OUTPUT:
    
Mild bibasilar atelectasis .