Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Lung volumes are low . This accentuates the size of the cardiac silhouette which is top normal . The aorta is mildly tortuous . Mediastinal and hilar contours are otherwise unremarkable . There is no pulmonary edema . Patchy bibasilar opacities likely reflect atelectasis . No pleural effusion or pneumothorax is seen . There are mild degenerative changes in the thoracic spine . Partially imaged are biliary stents within the right upper quadrant .
    OUTPUT:
    
Patchy bibasilar opacities likely reflect atelectasis in the setting of low lung volumes , but infection can not be completely excluded .