Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The cardiac , mediastinal and hilar contours appear stable . Increased relative density of the left lung compared to the right may be due to an asymmetry in positioning . No definite focal opacity is visualized . There is no pneumothorax or pleural effusion . Bony structures are unremarkable .
    OUTPUT:
    
No evidence of acute disease .