Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Opacity is seen at the left lung base is noted . There is no pleural effusion or pneumothorax . The cardiac silhouette remains mildly enlarged . The hilar structures are unremarkable . Sternotomy wires are again seen with frature through the second one from the top , as on prior .
    OUTPUT:
    
Opacity at the left lung base is likely atelectasis , although , could represent pneumonia in the correct clinical setting .