Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Stable enlargement of the cardiac silhouette . There is increased retrocardiac density , which may be artifactual . The mediastinal and hilar contours are normal . The pulmonary vasculature is normal . Lungs are clear . There is a small right pleural effusion . No pneumothorax is seen .
    OUTPUT:
    
1 . Increased retrocardiac density , which is likely artifactual due to poor inspiration and decreased penetration , considering there is also increased density overlying the vertebrae . However , pneumonia can not be excluded . 2 . Small right pleural effusion .