Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Patient is status post left lower lobe resection , with a moderate to large left - sided pneumothorax measuring approximately 7 .4 cm in greatest dimension . On expiratory view , there is mild rightward mediastinal shift . On inspiratory view , there is no mediastinal shift . Left lower lobe opacity is likely a combination of atelectasis and postsurgical change , including fluid . The right lung is grossly clear . New electronic device projects over the left perihilar region .
    OUTPUT:
    
Moderate to large left sided pneumothorax measuring approximately 7 .4 cm in greatest dimension . There is mild rightward mediastinal shift on expiratory view , however there is no mediastinal shift on inspiratory view .