Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Frontal and lateral radiographs of the chest demonstrate increased opacification of the left base , likely secondary to atelectasis . There is a small left - sided pleural effusion . The cardiomediastinal and hilar contours are unchanged . Multiple known left lateral and posterior rib fractures are better assessed on recent CT of the chest . There is no pneumothorax or consolidation .
    OUTPUT:
    
Small left - sided pleural effusion . Known left lateral and posterior rib fractures are better assessed on recent CT of the chest .