Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Linear bibasilar opacity is likely atelectasis . Blunting of the left lateral costophrenic angle is again seen , potentially due to additional atelectasis or potentially small effusion . Elsewhere , lungs are clear . Cardiomediastinal silhouette is stable . Old healed right posterior rib fracture is again noted . No acute osseous abnormality .
    OUTPUT:
    
Bibasilar atelectasis . Possible trace left pleural effusion . Otherwise no acute cardiopulmonary process .