Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Prior pneumothorax on the left has resolved . Multiple recent left - sided rib fractures and healed right - sided rib fractures are again noted . There is increased opacity at the left base , projecting medially on the PA view and posteriorly on the lateral view , with associated inferior hilar retraction compatible with volume loss . This thus likely represents a combination of significant left lower lobe atelectasis with a degree of left pleural fluid , though the relative contributions of these two processes to the current findings is difficult to discern . The right lung is well aerated and clear . There is no evidence of pneumonia . Hilar and cardiomediastinal contours are unchanged , accounting for inferior displacement of the left hilus . Postoperative changes are noted in the left shoulder , incompletely evaluated .
    OUTPUT:
    
Multiple left - sided rib fractures again noted , though there has been resolution of prior left pneumothorax . Significant increase in left lower lobe volume loss , likely with a degree of left pleural fluid .