Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Low lung volumes persist . The heart size is mild to moderately enlarged , and accentuated by low lung volumes . The mediastinal contours are unchanged , and the hilar contours are normal . Pulmonary vascularity is not engorged . Subsegmental atelectasis in the left lung base is again demonstrated . No focal consolidation , pleural effusion or pneumothorax is identified . There are multilevel degenerative changes in the thoracic spine with anterior bridging osteophytes .
    OUTPUT:
    
Subsegmental left basilar atelectasis . Otherwise no acute cardiopulmonary abnormality .