Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Heart size remains mildly enlarged . The mediastinal and hilar contours are unchanged with dense atherosclerotic calcification again seen in the thoracic aorta . The aorta remains tortuous . Pulmonary vasculature is not engorged . Streaky linear opacities in the lung bases likely reflect areas of atelectasis . No focal consolidation , pleural effusion or pneumothorax is present . Old bilateral rib fractures are noted .
    OUTPUT:
    
Mild bibasilar atelectasis .