Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There is a left lower lobe opacity , which most likely represents atelectasis , but pneumonia should be considered in the appropriate clinical setting . There are no pleural effusions or pneumothorax . Mild pulmonary vascular congestion , without overt pulmonary edema . Cardiomediastinal silhouette remains enlarged . Median sternotomy wires are intact .
    OUTPUT:
    
1 . Left lower lobe opacity , which likely represents atelectasis , but pneumonia should be considered in the appropriate clinical setting . 2 . Mild pulmonary vascular congestion without overt pulmonary edema .