Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Cardiac silhouette size remains mildly enlarged . The mediastinal contour is unchanged with unfolding of the thoracic aorta again noted . Pulmonary vasculature is not engorged . Hilar contours are normal . Subsegmental atelectasis is demonstrated in the lung bases . No focal consolidation , pleural effusion or pneumothorax is present . There are no acute osseous abnormalities .
    OUTPUT:
    
Mild bibasilar atelectasis .