Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Single chest drain remains in the right hemithorax . No right pneumothorax . The right lung shows improved aeration compared to the previous radiograph . Slight decrease in the mediastinal shift to the right . The cardiothoracic index is normal . Compensatory hyperinflation of the left lung with herniation across the midline . Increased density in the medial aspect of the left lower lobe appears similar compared to imaging done yesterday .
    OUTPUT:
    
No right - sided pneumothorax . Mild interval improvement of the right lung aeration as well as decreasing mediastinal shift . Opacity in the lower aspect of the left lung is unchanged .