Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Lung volumes are low . Heart size is mild to moderately enlarged , not substantially changed from the prior exam . The mediastinal and hilar contours are unremarkable . The pulmonary vasculature is not engorged . Streaky opacities in the lung bases likely reflect areas of atelectasis . No focal consolidation , pleural effusion or pneumothorax is identified . No acute osseous abnormalities noted .
    OUTPUT:
    
Mild bibasilar atelectasis .