Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Left basilar opacity is seen silhouetting the hemidiaphragm . Superimposed bibasilar parenchymal opacities are also seen . Superiorly , lungs are clear . Cardiomediastinal silhouette is within normal limits . No acute osseous abnormalities .
    OUTPUT:
    
Left basilar opacity in part due to a pleural effusion . Bibasilar streak opacities likely atelectasis noting that infection can not be excluded .