Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Mild cardiomegaly is unchanged compared to the prior exams dated back to ___ . There is mild pulmonary vascular congestion , otherwise the hilar and mediastinal contours are normal . There is no pleural effusion or pneumothorax . Redemonstrated are hyperinflated lungs with an enlarged retrosternal air space , consistent with COPD . Subtle opacity at the right lung base may represent pneumonia . The visualized osseous structures are unremarkable .
    OUTPUT:
    
Subtle opacity at the right lung base may be concerning for pneumonia .