Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Lungs are low in volume but appear clear . Minimal linear bibasilar atelectasis is similar to that on the prior study . There is a small left pleural effusion . No pneumothorax . The heart is mildly enlarged with normal cardiomediastinal silhouette .
    OUTPUT:
    
Small left pleural effusion .