Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Cardiac , mediastinal and hilar contours are normal . There are mild calcifications of the aortic knob . Linear opacities within the left lung base are compatible with scarring or linear atelectasis . There is no focal consolidation , pleural effusion or pneumothorax . Mild degenerative changes are noted in the thoracic spine .
    OUTPUT:
    
No acute cardiopulmonary process .