Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: AP portable upright view of the chest . There is a small to moderate left pneumothorax new from prior . Evaluation for mediastinal shift is limited due to positioning though mild rightward mediastinal shift is difficult to exclude . Extensive bilateral pulmonary opacities are reflective of known severe interstitial fibrosis . Bony structures appear intact .
    OUTPUT:
    
Moderate left pneumothorax . Mild rightward shift difficult to exclude given positioning . Background severe pulmonary fibrosis .