Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Heart size is mildly enlarged . The mediastinal and hilar contours are unremarkable . Lung volumes are low with crowding of bronchovascular structures , but no overt pulmonary edema . Opacification of the left base reflects a combination of a moderate size pleural effusion and left basilar atelectasis . Minimal atelectasis is also noted in the right lung base . Known left - sided small pneumothorax is not clearly seen on the current exam . Multiple displaced left - sided rib fractures are again noted .
    OUTPUT:
    
1 . No definite pneumothorax seen on the current exam . 2 . Moderate left pleural effusion with left basilar opacification likely reflective of compressive atelectasis . 3 . Multiple left - sided rib fractures .