Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Low lung volumes are present causing crowding of the bronchovascular structures and linear bibasilar opacities compatible with atelectasis . Cardiomediastinal and hilar contours are unchanged with tortuosity of the thoracic aorta again noted . No pleural effusion or pneumothorax is seen . The sternotomy wires are intact . Patient is status post CABG . Bilateral total shoulder replacements are partially imaged .
    OUTPUT:
    
Low lung volumes with bibasilar atelectasis .