Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The cardiac and mediastinal silhouettes appear within normal limits . However , on the lateral view , there is slight loss of the retrosternal clear space , which in a patient of this age may represent a small amount of residual thymic tissue . There are no focal pulmonary opacities , pleural effusions , or evidence of pneumothorax . The osseous structures remarkable .
    OUTPUT:
    
1 . No evidence of acute cardiopulmonary disease . 2 . Slight decrease in the retrosternal clear space may represent residual thymic tissue in a patient of this age .