Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Heart size is normal . Mediastinal and hilar contours are unchanged . Lung volumes are low with crowding of bronchovascular structures but no overt pulmonary edema . Linear subsegmental atelectasis is noted in both lower lobes . No focal consolidation , pleural effusion or pneumothorax is detected . There are no acute osseous abnormalities .
    OUTPUT:
    
Low lung volumes with subsegmental bibasilar atelectasis . No radiographic evidence for pneumonia .