Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Portable AP upright chest radiograph was provided . Bibasilar opacity , mild and likely reflects atelectasis , though small effusions are impossible to exclude . Patient is rotated to the right , which limits evaluation . Allowing for technical limitations , there is no definite sign of pulmonary edema or new consolidation since prior exam . The heart size can not be assessed . Bony structures appear intact .
    OUTPUT:
    
Mild bibasilar opacity in the setting of low lung volumes could represent small effusion or atelectasis . Limited due to rotation . No significant change from prior .