Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: AP portable upright view of the chest . Mild cardiomegaly is again noted . Midline sternotomy wires and mediastinal clips are present . Increased retrocardiac opacity is concerning for a left lower lobe pneumonia . Band like opacity in the right mid lung may represent atelectasis . No large effusion or pneumothorax is seen . Imaged osseous structures are intact .
    OUTPUT:
    
Mild cardiomegaly , retrocardiac opacity concerning for left lower lobe pneumonia . Right midlung atelectasis .