Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: AP and lateral views of the chest . Again seen are relatively linear bibasilar opacities , left worse than right . There may have been interval progression at the left lung base compared to prior . Superiorly , the lungs remain clear . Cardiomediastinal silhouette is unchanged . Multilevel vertebroplasty changes are again seen .
    OUTPUT:
    
Persistent bibasilar opacities , potentially due to atelectasis or scarring , noting that infection or aspiration is not completely excluded .