Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Frontal view of the chest was obtained . The heart is top normal size . The mediastinal contours are stable . Ill - defined opacity overlying the medial right lung corresponds to the mass seen on prior CT torso . There is increased aeration of the left lung , which may be due to improved inspiratory effort . No pneumothorax or substantial pleural effusion . Deviation of the trachea may be positional and is similar to prior . Wires of a left chest wall pacer terminate in stable position .
    OUTPUT:
    
Improved aeration of left lung , which may be due better inspiratory effort . Ill - defined opacity overlying the medial right lung corresponds to the mass seen on prior CT torso .