Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There may be a very small left pneumothorax , as well as a small residual left pleural effusion . An opacity at the left lung base , best seen on the lateral view , is probably atelectasis , but infection can not be excluded . The cardiomediastinal silhouette is stable . There are no acute skeletal findings .
    OUTPUT:
    
1 . Possible very small left pneumothorax . 2 . Small residual left pleural effusion . 3 . Likely left lower lobe rounded atelectasis , alternatively pneumonia . These findings were discussed with Dr . ___ by Dr . ___ ___ telephone at approximately 4 p .m . on the day of the study .