Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Cardiac , mediastinal and hilar contours are normal . Pulmonary vasculature is normal . Linear opacities in the lung bases are compatible with areas of subsegmental atelectasis . No focal consolidation , pleural effusion or pneumothorax is visualized . No acute osseous abnormality is detected .
    OUTPUT:
    
Bibasilar subsegmental atelectasis .