Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The cardiomediastinal and hilar contours are within normal limits . The lungs demonstrate an ill - defined opacity in the left lower lung with air bronchograms which was not present on prior exam and is concerning in this clinical setting for pneumonia . There is no pleural effusion or pneumothorax .
    OUTPUT:
    
Left lower lobe pneumonia .