Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The heart size is top normal . The aorta is mildly tortuous and diffusely calcified . The mediastinal and hilar contours are otherwise within normal limits . The pulmonary vascularity is not engorged . Minimal blunting of the costophrenic angles posteriorly on the lateral view may reflect chronic pleural thickening . There is no large pleural effusion or pneumothorax . Mild atelectatic changes are noted within the left lung base . No acute osseous abnormalities are seen . There are multilevel degenerative changes in the thoracic spine .
    OUTPUT:
    
Minimal left basilar atelectasis .