Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: A linear opacities at the bilateral lung bases may represent subsegmental atelectasis versus scarring . No other focal opacities are identified . Cardiomediastinal and hilar contours are unremarkable . There is no pleural effusion or pneumothorax . Atherosclerotic calcifications are noted at the aortic knob .
    OUTPUT:
    
Bibasilar opacities suggestive of atelectasis howver infection can not be excluded .