Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Faint opacities in the lung bases are likely due to atelectasis . There are no other focal airspace opacities to suggest infection . The lungs are well expanded . The heart is at the upper limits of normal as on the previous study . The mediastinal and hilar contours are normal . There is no pleural effusion or pneumothorax . The aorta is calcified and tortuous .
    OUTPUT:
    
Mild bibasilar atelectasis without evidence to suggest pneumonia .