Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The heart is at the upper limits of normal size with a left ventricular configuration . There is mild unfolding of the thoracic aorta . The mediastinal and hilar contours appear unchanged . There are streaky posterior basilar opacities in the left lower lobe and probably in the lingula which are more suggestive of atelectasis than pneumonia , although an infectious process is difficult to completely exclude . Elsewhere , the lungs appear clear . There are no pleural effusions or pneumothorax . Mild degenerative changes are similar along the mid thoracic spine with slight minimal wedging of mid thoracic vertebral bodies that appears unchanged .
    OUTPUT:
    
Streaky left basilar opacities , more suggestive of atelectasis than pneumonia , although an infectious etiology is difficult to entirely exclude .