Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: PA and lateral chest views were obtained with patient in upright position . Comparison is made with the next preceding similar study of ___ . Chest findings are grossly unaltered . The left - sided apical small pneumothorax is still present , although it has diminished in size again . The maximal pleural layer separation in the apical area is about 1 cm . Pulmonary parenchyma appears clear and the post-operatively small remaining hematoma has now formed into a linear scar as can be identified on the lateral view . No new abnormalities .
    OUTPUT:
    
Persistent very small left - sided apical pneumothorax . No other significant abnormalities remaining .