Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The cardio mediastinal silhouettes are grossly unchanged in comparison to prior film . There is again seen a calcified thoracic aorta . The bilateral hila are normal . There has been interval development of a left lower lobe / retrocardiac opacity , possibly with a visualized air bronchogram , which obscures the left hemidiaphragm . Additionally , there is loss of definition of the right hemidiaphragm . There are also small bilateral pleural effusions . This may represent new left lower lobe or possibly bilateral lower lobe aspiration versus pneumonia , especially given clinical context . This appearance could also simply represent bibasilar relaxation atelectasis secondary to small bilateral pleural effusions . There are no pneumothoraces .
    OUTPUT:
    
New left lower lobe / retrocardiac opacity , as well as right lower lobe opacification , which is concerning for left lower lobe versus bilateral lower lobe aspiration or pneumonia . Less likely , may also represent bibasilar atelectasis secondary to small bilateral pleural effusions .