Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Cardiac silhouette size is normal . Mediastinal and hilar contours are unremarkable . Pulmonary vasculature is normal . Subsegmental atelectasis is seen in the left lung base . Right lung is clear . No pleural effusion or pneumothorax is present . No acute osseous abnormalities demonstrated . Widening of the left acromioclavicular joint may be posttraumatic or postsurgical .
    OUTPUT:
    
No acute cardiopulmonary abnormality .