Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Lung volumes are low . There is mild atelectasis at the bilateral lung bases . No focal consolidation , edema , effusion , or pneumothorax . Prominence of the mediastinum is overall unchanged , consistent with ectatic aorta . The heart is normal in size . No acute osseous abnormality . Degenerative changes at the AC joints bilaterally are again seen .
    OUTPUT:
    
Low lung volumes with bibasilar atelectasis . No focal pneumonia .