Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There are relatively low lung volumes and basilar atelectasis . Left base opacity may be due to atelectasis however , underlying consolidation due to pneumonia is not excluded in the appropriate clinical setting . No large pleural effusion is seen . There is no pneumothorax . Cardiac and mediastinal silhouettes are grossly stable .
    OUTPUT:
    
Left base opacity , could be due to atelectasis , but pneumonia may be present in the appropriate clinical setting .