Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Frontal and lateral views of the chest were obtained . There is subtle opacity at the lateral left lung base , which could be due to atelectasis or infection . The right lung is clear . There is no large pleural effusion . The cardiac and mediastinal silhouettes are stable .
    OUTPUT:
    
Subtle lateral left base opacity could be due to atelectasis or infection .