Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: PA and lateral views of the chest were provided . There is mild residual opacity within the left lower lobe which could represent atelectasis or residual pneumonia . No large effusion or pneumothorax . The heart and mediastinal contour appears normal . Bony structures are intact .
    OUTPUT:
    
Residual opacity in the left lower lobe could represent atelectasis or pneumonia .