Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: PA and lateral views of the chest provided . Midline sternotomy wires are noted . There is persistent left lower lobe atelectasis accounting for retrocardiac opacity . Difficult to exclude a superimposed pneumonia though overall pattern appears similar . Right lung is clear . No large effusion or pneumothorax . Overall cardiomediastinal silhouette appears similar to prior
    OUTPUT:
    
Persistent left lower lobe atelectasis .