Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There has been interval removal of the left chest tube without substantial pneumothorax . Lung volumes are low with unchanged appearance of biapical opacities and small bilateral pleural effusions . Opacification overlying the spine obscures the left hemidiaphragm . Mediastinal contours and mild cardiomegaly are stable .
    OUTPUT:
    
1 . No substantial pneumothorax . 2 . Opacification overlying the spine likely represents a combination of atelectasis , pleural effusion , and postoperative changes although the pneumonia can not be excluded if there is clinical concern .