Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The cardiomediastinal silhouette and pulmonary vasculature are unchanged since the prior examination and unremarkable . Mild right infrahilar opacity is not significantly changed since the prior examination . There is no pneumothorax or pleural effusion . The lungs are clear .
    OUTPUT:
    
No acute intrathoracic abnormality .