Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: PA and lateral views of the chest . Bibasilar opacities are unchanged and represent either atelectasis or pneumonia . There is hyperinflation of the lungs and flattening of the diaphragms , suggesting obstructive lung disease . A Y - type tracheal stent is better seen on the lateral view and in place . There is no pleural effusion or pneumothorax .
    OUTPUT:
    
1 . Unchanged bibasilar opacifications , representing either atelectasis or pneumonia . 2 . Y-type tracheal stent in place . 3 . Lung changes consistent with COPD .