Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The lung volumes are low . Since the prior exam , the mild pulmonary edema has improved . A more focal opacity at the right base is present , may represent pneumonia or atelectasis , though appears slightly improved from prior exams . A linear opacity at the left base is likely atelectasis . There is no pleural effusion or pneumothorax . The cardiomediastinal silhouette is unchanged . The heart size is normal .
    OUTPUT:
    
Improved pulmonary edema with a persistent right basilar opacity , which may represent pneumonia or atelectasis .