Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Cardiac silhouette size is normal . Mediastinal and hilar contours are normal . The pulmonary vascularity is normal . Linear opacities in the lung bases are compatible with either subsegmental atelectasis versus scarring . No focal consolidation , pleural effusion , or pneumothorax is seen . There are no acute osseous abnormalities .
    OUTPUT:
    
Bibasilar subsegmental atelectasis or scarring .