Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The cardiac silhouette has decreased in size since ___ but appears relatively similar to ___ . The mediastinal widening has also improvfed since ___ . The lungs are clear without focal opacity , pleural effusion or pneumothorax . There is bibasilar atelectasis which is likely due to low lung volumes .
    OUTPUT:
    
No opacity concerning for pneumonia . Interval improvement of cardiomegaly since ___ .