Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The heart is normal in size . The aorta is mildly tortuous . The mediastinal and hilar contours appear within normal limits . There are no pleural effusions or pneumothorax . There is an irregular density that is new over the short interval projecting over the left upper lobe but only on the frontal view suggesting an artifact ; a repeat view was performed with a hair clip removed , showing the area to be clear .
    OUTPUT:
    
No definite evidence of acute disease .