Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There are low lung volumes and mild left base atelectasis . Left base opacity has decreased as compared to the prior study . No pleural effusion or pneumothorax is seen . The cardiac and mediastinal silhouettes are stable and unremarkable .
    OUTPUT:
    
Low lung volumes and mild left base atelectasis . Left base opacity is significantly decreased compared to prior .