Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Single frontal view of the chest was obtained . Midline tracheostomy tube is again seen . There is mild left greater than right bibasilar atelectasis . Minimal blunting of the left costophrenic angle could be due to a trace effusion . No definite focal consolidation is seen . The cardiac silhouette is top normal . The aortic knob is calcified .
    OUTPUT:
    
Possible trace left pleural effusion with overlying atelectasis .