Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Frontal and lateral radiographs of the chest demonstrate intact median sternotomy wires . Compared to the prior radiograph , there is improved inspiratory volumes . The cardiac contour is normal . The mediastinal contours are normal aside from a slightly tortuous descending aorta . The lungs are clear with no focal opacity . No pneumothorax or pleural effusion is seen .
    OUTPUT:
    
No evidence of acute infection , pleural effusion , or pneumothorax .