Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The heart is normal in size . The mediastinal and hilar contours are otherwise unremarkable . A moderate - to - large hiatal hernia with an air - fluid level projects along the lower central mediastinum . There is no pleural effusion or pneumothorax . The lungs appear clear . Although the hiatal hernia is somewhat more conspicuous , otherwise , there has been no significant change .
    OUTPUT:
    
Moderate - to - large hiatal hernia . No evidence of acute disease .