Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Patient is status post median sternotomy . Left lower lobe opacity is worrisome for pneumonia . Cardiac silhouette is top - normal to mildly enlarged . Mediastinal contours are stable . No large pleural effusion is seen . There is no evidence of pneumothorax .
    OUTPUT:
    
Left lower lobe opacity worrisome for pneumonia .