Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Cardiac silhouette is mildly enlarged but unchanged compared to the previous study . Thoracic aorta is tortuous . Mediastinal contours are stable . Lung volumes are low , but lungs appear clear with no focal consolidation to suggest pneumonia . No pleural effusions . No pneumothorax .
    OUTPUT:
    
No significant changes compared to the previous study . No radiologic evidence of acute pneumonia .