Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Frontal and lateral views of the chest . The cardiac silhouette is enlarged since ___ , which may reflect either cardiomegaly or a pericardial effusion . The lungs are clear without focal consolidation , pleural effusion , or pneumothorax .
    OUTPUT:
    
Interval enlargement of the cardiac silhouette , representing either new borderline cardiomegaly or a pericardial effusion .