Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Lordotic positioning and low inspiratory volumes . Compared with the prior study , the right apical pneumothorax remains relatively small , but is slightly larger than on the prior study . No discrete right - sided atelectasis is identified . The enlarged cardiomediastinal silhouette with sternotomy wires is grossly unchanged . Mild prominence of vessels is likely accentuated by low inspiratory volumes . Doubt overt CHF The degree of increased retrocardiac density has improved , with the left hemidiaphragm now visible . There is atelectasis in left mid zone . No gross effusion is identified .
    OUTPUT:
    
Right upper zone pneumothorax has increased notably compared with ___ , but remains relatively small . It lies between the right third and fourth posterior ribs . Interval improvement in the degree of retrocardiac opacity . Otherwise , doubt significant change allowing for differences in positioning .