Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There is mild hyperexpansion of the lung , similar to prior to studies . There is no focal airspace opacity . Atelectasis at the lung bases is mild . The cardiomediastinal silhouette and hilar contours are normal . There is no pleural effusion or pneumothorax .
    OUTPUT:
    
Mild atelectasis at the lung bases and stable hyperexpansion . No acute cardiopulmonary abnormality .