Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The lungs are clear . The hilar and mediastinal silhouette is normal . The heart size is stable and at the upper limit of normal . There is no pneumothorax or pleural effusion . Pulmonary vascularity is normal . The aorta is stably tortuous .
    OUTPUT:
    
No acute intrathoracic process .