Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The heart size , mediastinal , and hilar contours are normal . The lungs are clear without pleural effusion , focal consolidation , or pneumothorax . Subtle distortion of the left perihilar markings on the frontal radiograph reflect radiation related changes better assessed on prior CT and unchanged in appearance . Bony structures appear intact .
    OUTPUT:
    
No acute intrathoracic process .