Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Single frontal chest radiograph demonstrates unremarkable hilar contours . Atherosclerotic calcifications are present in the aortic arch . The cardiac silhouette is not enlarged . There are bibasilar opacifications , left greater than right which may represent atelectasis though superimposed infectious process or aspiration is not excluded . No pneumothorax identified . Mild blunting of the bilateral costophrenic angles suggests small bilateral pleural effusions . Multilevel degenerative changes are present in the thoracic spine .
    OUTPUT:
    
Bibasilar opacification which may reflect atelectasis or pneumonia . Clinical correlation is advised . Possible trace pleural effusions .