Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Extensive opacification of the left hemithorax likely reflects primarily the presence of a large pleural effusion , likely hemothorax , with associated left basilar atelectasis , with mild rightward shift of mediastinal structures . Contusion within the left lung base can not be excluded . Low lung volumes are seen in the right lung with patchy atelectasis in the right lung base . No pneumothorax is detected . Displaced fracture of the left seventh posterior rib is re - demonstrated . There is no overt pulmonary edema in the right lung .
    OUTPUT:
    
Large left pleural effusion , likely hemothorax , with associated left basilar atelectasis , although lung contusion is not excluded . Displaced left seventh posterior rib fracture .