Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The cardiac , mediastinal and hilar contours appear unchanged including stable cardiomegaly . There is no definite pleural effusion or pneumothorax . Each hilum is mildly prominent , as before . Prominence of each hilum is probably due to mild enlargement of central pulmonary arteries , not significantly changed . The lungs appear clear .
    OUTPUT:
    
Similar enlargement of central pulmonary arteries , but no definite evidence for acute disease .