Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Frontal and lateral chest radiographs demonstrate a mildly enlarged heart . The lungs are well aerated and clear . There is no pneumothorax or pleural effusion . The left hemidiaphragm is somewhat flattened , unchanged in appearance compared to prior exam .
    OUTPUT:
    
Mild cardiac enlargement . No focal opacity .