Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: A moderate to large left pleural effusion is present . No definite pneumothorax is identified . Left basilar opacification may reflect compressive atelectasis though infection or contusion is difficult to exclude . The right lung appears grossly clear . There is no pulmonary vascular congestion . Heart size is difficult to determine given the presence of the left basilar opacification and pleural effusion . Calcification of the aortic knob is visualized . Displaced fractures of multiple left - sided posterior ribs are noted , likely the left ___ , ___ , and 10th ribs .
    OUTPUT:
    
Moderately large left pleural effusion with left basilar opacification likely reflecting compressive atelectasis though infection or contusion is difficult to exclude . Multiple displaced left - sided rib fractures . No pneumothorax identified .