Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There are bibasilar opacities , which may reflect a combination of effusions and atelectasis , though pneumonia or aspiration can not be excluded . Upper lungs are clear . There is no pneumothorax . Mediastinal and hilar contours are within normal limits . No overt interstitial edema is identified . Evaluation of the cardiac silhouette is limited due to basilar opacities .
    OUTPUT:
    
Bibasilar opacities , possible effusions and atelectasis , but pneumonia is also within the differential . Formal PA and lateral may be helpful for further characterization .