Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Lung volumes are slightly reduced compared to the previous exam . The heart size remains mildly enlarged . The mediastinal and hilar contours are unremarkable . There is crowding of the bronchovascular structures as a result of low lung volumes . Patchy opacities are seen in the lung bases . This is nonspecific , and could reflect areas of atelectasis , but aspiration or infection is not excluded . No pleural effusion or pneumothorax is demonstrated . No acute osseous abnormalities .
    OUTPUT:
    
Low lung volumes . Patchy bibasilar airspace opacities may be due to atelectasis , but aspiration or infection is not excluded .