Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Subtle left lower lobe opacity is not well substantiated on the lateral view , is again seen which may be due to atelectasis ; however , as also noted on the prior study , pneumonia is not excluded in the appropriate clinical setting . No pleural effusion or pneumothorax is seen . The cardiac and mediastinal silhouettes are stable . Hilar contours are stable .
    OUTPUT:
    
Subtle left lower lobe opacity is not well substantiated on the lateral view , is again seen which may be due to atelectasis ; however , as also noted on the prior study , pneumonia is not excluded in the appropriate clinical setting