Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Lower lung volumes noted on the current exam . Bibasilar opacities , left greater than right may be secondary to atelectasis . Superiorly , lungs are clear . Cardiomediastinal silhouette is stable . Right shoulder arthroplasty changes are noted . Old left lateral rib fractures are noted .
    OUTPUT:
    
Bibasilar opacities likely atelectasis , to be correlated clinically . No pulmonary edema .