Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There is abnormal lucency in front of the heart best seen on the lateral view just behind the sternum . This correlates with the pneumothorax seen on the prior CT scan . Allowing for differences in technique this appears smaller than on the prior CT scan . Heart size is upper limits of normal . There is no focal consolidation . There is atelectasis at the lung bases . There is wedging of several mid to lower thoracic vertebral bodies and calcification of the anterior longitudinal ligament consistent with DISH . There is mild osteopenia .
    OUTPUT:
    
Retrosternal pneumothorax as described above .