Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Heart size is normal . Mediastinal and hilar contours are unremarkable . Lungs are clear . Pulmonary vasculature is normal . No pleural effusion or pneumothorax is seen . Minimal subsegmental atelectasis is noted within the left lung base . There are no acute osseous abnormalities identified . Mild degenerative changes are noted in the thoracic spine .
    OUTPUT:
    
No acute cardiopulmonary process .