Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There are low lung volumes . There is a hazy opacity at the right lung base which may represent atelectasis but an infectious process can not be excluded . Cardiomediastinal silhouette is slightly enlarged , similar to prior exam . There is no pneumothorax or pleural effusion .
    OUTPUT:
    
Hazy opacity at the right lung base which may represent atelectasis but an infectious process is not excluded .