Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The heart size is within normal limits . The mediastinal contours are largely unchanged demonstrating a moderately sized but stable hiatal hernia . The lungs demonstrate mild bibasilar atelectasis , more pronounced on the left . There is no pleural effusion or pneumothorax .
    OUTPUT:
    
Hiatal hernia , but no acute cardiopulmonary process .