Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The heart size is normal . The aorta is mildly unfolded with atherosclerotic calcification seen diffusely throughout the aorta . The hilar contours are normal . Linear opacities in both lung bases are compatible with subsegmental atelectasis . No focal consolidation , pneumothorax , or pleural effusion is present . There are multilevel moderate degenerative changes in the imaged thoracic spine .
    OUTPUT:
    
Bibasilar subsegmental atelectasis . No radiographic evidence for pneumonia .