Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Cardiac , mediastinal and hilar contours appear unchanged . The lungs appear clear aside from minor atelectasis at the lung bases . There is no pleural effusion or pneumothorax . Hemidiaphragms are flattened . Patient is status post bilateral shoulder replacements , incompletely characterized . Similar degenerative changes are present along mid thoracic levels .
    OUTPUT:
    
No evidence of acute cardiopulmonary disease .