Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: AP and lateral views of the chest are compared to previous exam from ___ . There is opacity at the left lung base laterally , also seen on the lateral view compatible with atelectasis versus infiltrate . Elsewhere , the lungs are clear of confluent consolidation but notable for prominent central indistinct vascular markings . Small effusion is noted on the left . Cardiac silhouette is enlarged but stable . Osseous structures again notable for posterior right rib fractures .
    OUTPUT:
    
Left basilar opacity , potentially due to atelectasis versus consolidation and probable trace effusion . Findings suggestive of pulmonary vascular congestion .