Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Single frontal view of the chest demonstrates low lung volumes , accentuating cardiac silhouette . The mediastinal and hilar contours are within normal limits . Mild unfolding of thoracic aorta is noted . The lungs are clear . There is no pneumothorax , vascular congestion , or pleural effusion .
    OUTPUT:
    
No evidence of pneumonia .