Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: In comparison to ___ chest radiograph , a left retrocardiac opacity has nearly resolved with minimal linear opacities remaining . Lungs are hyperinflated and note is made of linear atelectasis or scarring at the right base . Small bilateral pleural effusions are also demonstrated . Heart size is normal and note is made of previous median sternotomy and aortic valve replacement
    OUTPUT:
    
Rapidly improved left lower lobe opacity . Such rapid improvement strongly favors atelectasis or aspiration over infectious pneumonia . Small bilateral pleural effusions .