Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Since the prior exam , the bibasilar opacities have worsened , particularly on the left . The apices of the lungs are clear . There is no pulmonary edema , pleural effusion , or pneumothorax . The cardiomediastinal silhouette is normal . High - density material in the mid thoracic spine is from a prior vertebroplasty .
    OUTPUT:
    
Worsening bibasilar opacities , which most likely represent atelectasis . No definite evidence of pneumonia .