Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: A right pigtail catheter is again seen . No well - defined pneumothorax is identified . Trace lucency at the right lung apex could reflect a tiny residual pneumothorax . The cardiomediastinal silhouette is stable . No CHF focal infiltrate or effusion is identified . Minimal biapical pleural thickening left greater the right is unchanged .
    OUTPUT:
    
As above . .