Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Linear opacity at the left lung base is most likely atelectasis . The lungs are otherwise clear . The cardiomediastinal silhouette is within normal limits . Left chest wall dual lead pacing device is identified . Colonic interposition seen below the right hemidiaphragm , as on prior . Lumbar spinal fixation hardware and intrathecal device are partially identified .
    OUTPUT:
    
No acute cardiopulmonary process .