Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The lungs are well expanded . Small opacity at the left lung base likely represents atelectasis . Lungs otherwise clear . There is small left pleural effusion and a probable trace right pleural effusion . No pneumothorax . The cardiomediastinal silhouette is unremarkable . Gaseous distention of the colon is noted .
    OUTPUT:
    
Opacity at the left lung base , likely representing atelectasis . Small left and probable trace right pleural effusions .