Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Lung volumes are low with chronic elevation of the right hemidiaphragm . A rounded retrocardiac opacity could represent aspiration or pneumonia at the left base in this patient with history of aspiration pneumonia . Plate - like opacity at the right base likely reflects atelectasis . No pneumothorax or significant pleural effusion is present . The heart size is normal . There are calcifications of the aortic arch . The patient is status post left shoulder hemiarthroplasty . There are severe degenerative changes of the right shoulder .
    OUTPUT:
    
Round left retrocardiac opacity , which may reflect aspiration or developing aspiration pneumonia . Recommend PA and lateral CXR for more complete assessment when the patient 's condition permits .