Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Single AP upright portable view of the chest was obtained . There are low lung volumes , which accentuate the bronchovascular markings . Left lower chest implanted neurostimulator is again seen and obscures the left costophrenic angle . There is bibasilar atelectasis . Patchy left base retrocardiac opacity could be due to atelectasis ; however , underlying consolidation due to aspiration or infection not excluded . No large pleural effusion is seen but trace pleural effusions would be difficult to exclude . There is no evidence of pneumothorax . The cardiac and mediastinal silhouettes are unremarkable .
    OUTPUT:
    
Low lung volumes , which accentuate the bronchovascular markings . Basilar atelectasis . Subtle patchy left base retrocardiac opacity may be due to atelectasis , although an early consolidation due to aspiration or infection is not excluded .