Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The cardiac silhouette size is normal . Mediastinal and hilar contours are unremarkable . Pulmonary vasculature is normal . Apart from subsegmental atelectasis in the left lung base , the lungs are clear . No pleural effusion or pneumothorax is present . Multilevel moderate degenerative changes are noted in the thoracic spine .
    OUTPUT:
    
No acute cardiopulmonary abnormality .