Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Mild - to - moderate enlargement of the cardiac silhouette is unchanged . The aortic knob is calcified . Mediastinal and hilar contours are stable . The pulmonary vascularity is not engorged . Mild bibasilar atelectasis is noted . No pleural effusion or pneumothorax is visualized . There are no acute osseous abnormalities .
    OUTPUT:
    
Mild bibasilar atelectasis .